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Search for "acrylates" in Full Text gives 104 result(s) in Beilstein Journal of Organic Chemistry.
Synthetic reactions driven by electron-donor–acceptor (EDA) complexes
- Zhonglie Yang,
- Yutong Liu,
- Kun Cao,
- Xiaobin Zhang,
- Hezhong Jiang and
- Jiahong Li
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
- trifluoromethylation (Scheme 25). A variety of olefins, such as ene carbamates, styrene, aliphatic olefins, vinyl ethers, and acrylates are compatible in this approach, affording corresponding β-(trifluoromethyl)alkynes with good to excellent yield. The bifunctionalization was achieved by an EDA-complex-initiated
Graphical Abstract
Scheme 1: The electron transfer process in EDA complexes.
Scheme 2: Synthesis of benzo[b]phosphorus oxide 3 initiated by an EDA complex.
Scheme 3: Mechanism of the synthesis of quinoxaline derivative 7.
Scheme 4: Synthesis of imidazole derivative 10 initiated by an EDA complex.
Scheme 5: Synthesis of sulfamoylation product 12 initiated by an EDA complex.
Scheme 6: Mechanism of the synthesis of sulfamoylation product 12.
Scheme 7: Synthesis of indole derivative 22 initiated by an EDA complex.
Scheme 8: Synthesis of perfluoroalkylated pyrimidines 26 initiated by an EDA complex.
Scheme 9: Synthesis of phenanthridine derivative 29 initiated by an EDA complex.
Scheme 10: Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex.
Scheme 11: Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32.
Scheme 12: Synthesis of phenanthridine derivative 38 initiated by an EDA complex.
Scheme 13: Synthesis of spiropyrroline derivative 40 initiated by an EDA complex.
Scheme 14: Synthesis of benzothiazole derivative 43 initiated by an EDA complex.
Scheme 15: Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex.
Scheme 16: Synthesis of indoline derivative 47 initiated by an EDA complex.
Scheme 17: Mechanism of the synthesis of spirocyclic indoline derivative 47.
Scheme 18: Synthesis of cyclobutane product 50 initiated by an EDA complex.
Scheme 19: Mechanism of the synthesis of spirocyclic indoline derivative 50.
Scheme 20: Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex.
Scheme 21: Synthesis of trifluoromethylated product 61 initiated by an EDA complex.
Scheme 22: Synthesis of indole alkylation product 64 initiated by an EDA complex.
Scheme 23: Synthesis of perfluoroalkylation product 67 initiated by an EDA complex.
Scheme 24: Synthesis of hydrotrifluoromethylated product 70 initiated by an EDA complex.
Scheme 25: Synthesis of β-trifluoromethylated alkyne product 71 initiated by an EDA complex.
Scheme 26: Mechanism of the synthesis of 2-phenylthiophene derivative 74.
Scheme 27: Synthesis of allylated product 80 initiated by an EDA complex.
Scheme 28: Synthesis of trifluoromethyl-substituted alkynyl product 84 initiated by an EDA complex.
Scheme 29: Synthesis of dearomatized fluoroalkylation product 86 initiated by an EDA complex.
Scheme 30: Mechanism of the synthesis of dearomatized fluoroalkylation product 86.
Scheme 31: Synthesis of C(sp3)–H allylation product 91 initiated by an EDA complex.
Scheme 32: Synthesis of perfluoroalkylation product 93 initiated by an EDA complex.
Scheme 33: Synthesis of spirocyclic indolene derivative 95 initiated by an EDA complex.
Scheme 34: Synthesis of perfluoroalkylation product 97 initiated by an EDA complex.
Scheme 35: Synthesis of alkylated indole derivative 100 initiated by an EDA complex.
Scheme 36: Mechanism of the synthesis of alkylated indole derivative 100.
Scheme 37: Synthesis of arylated oxidized indole derivative 108 initiated by an EDA complex.
Scheme 38: Synthesis of 4-ketoaldehyde derivative 111 initiated by an EDA complex.
Scheme 39: Mechanism of the synthesis of 4-ketoaldehyde derivative 111.
Scheme 40: Synthesis of perfluoroalkylated olefin 118 initiated by an EDA complex.
Scheme 41: Synthesis of alkylation product 121 initiated by an EDA complex.
Scheme 42: Synthesis of acylation product 123 initiated by an EDA complex.
Scheme 43: Mechanism of the synthesis of acylation product 123.
Scheme 44: Synthesis of trifluoromethylation product 126 initiated by an EDA complex.
Scheme 45: Synthesis of unnatural α-amino acid 129 initiated by an EDA complex.
Scheme 46: Synthesis of thioether derivative 132 initiated by an EDA complex.
Scheme 47: Synthesis of S-aryl dithiocarbamate product 135 initiated by an EDA complex.
Scheme 48: Mechanism of the synthesis of S-aryl dithiocarbamate product 135.
Scheme 49: Synthesis of thioether product 141 initiated by an EDA complex.
Scheme 50: Mechanism of the synthesis of borate product 144.
Scheme 51: Synthesis of boronation product 148 initiated by an EDA complex.
Scheme 52: Synthesis of boration product 151 initiated by an EDA complex.
Scheme 53: Synthesis of boronic acid ester derivative 154 initiated by an EDA complex.
Scheme 54: Synthesis of β-azide product 157 initiated by an EDA complex.
Scheme 55: Decarboxylation reaction initiated by an EDA complex.
Scheme 56: Synthesis of amidated product 162 initiated by an EDA complex.
Scheme 57: Synthesis of diethyl phenylphosphonate 165 initiated by an EDA complex.
Scheme 58: Mechanism of the synthesis of diethyl phenylphosphonate derivative 165.
Scheme 59: Synthesis of (Z)-2-iodovinyl phenyl ether 168 initiated by an EDA complex.
Scheme 60: Mechanism of the synthesis of (Z)-2-iodovinyl phenyl ether derivative 168.
Scheme 61: Dehalogenation reaction initiated by an EDA complex.
The preparation and properties of 1,1-difluorocyclopropane derivatives
- Kymbat S. Adekenova,
- Peter B. Wyatt and
- Sergazy M. Adekenov
Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25
Graphical Abstract
Scheme 1: Synthesis of 1,1-difluoro-2,3-dimethylcyclopropane (2).
Scheme 2: Cyclopropanation via dehydrohalogenation of chlorodifluoromethane.
Scheme 3: Difluorocyclopropanation of methylstyrene 7 using dibromodifluoromethane and zinc.
Scheme 4: Synthesis of difluorocyclopropanes from the reaction of dibromodifluoromethane and triphenylphosphi...
Scheme 5: Generation of difluorocarbene in a catalytic two-phase system and its addition to tetramethylethyle...
Scheme 6: The reaction of methylstyrene 7 with chlorodifluoromethane (11) in the presence of a tetraarylarson...
Scheme 7: Pyrolysis of sodium chlorodifluoroacetate (12) in refluxing diglyme in the presence of alkene 13.
Scheme 8: Synthesis of boron-substituted gem-difluorocyclopropanes 16.
Scheme 9: Addition of sodium bromodifluoroacetate (17) to alkenes.
Scheme 10: Addition of sodium bromodifluoroacetate (17) to silyloxy-substituted cyclopropanes 20.
Scheme 11: Synthesis of difluorinated nucleosides.
Scheme 12: Addition of butyl acrylate (26) to difluorocarbene generated from TFDA (25).
Scheme 13: Addition of difluorocarbene to propargyl esters 27 and conversion of the difluorocyclopropenes 28 t...
Scheme 14: The generation of difluorocyclopropanes using MDFA 30.
Scheme 15: gem-Difluorocyclopropanation of styrene (32) using difluorocarbene generated from TMSCF3 (31) under...
Scheme 16: Synthesis of a gem-difluorocyclopropane derivative using HFPO (41) as a source of difluorocarbene.
Scheme 17: Cyclopropanation of (Z)-2-butene in the presence of difluorodiazirine (44).
Scheme 18: The cyclopropanation of 1-octene (46) using Seyferth's reagent (45) as a source of difluorocarbene.
Scheme 19: Alternative approaches for the difluorocarbene synthesis from trimethyl(trifluoromethyl)tin (48).
Scheme 20: Difluorocyclopropanation of cyclohexene (49).
Scheme 21: Synthesis of difluorocyclopropane derivative 53 using bis(trifluoromethyl)cadmium (51) as the diflu...
Scheme 22: Addition of difluorocarbene generated from tris(trifluoromethyl)bismuth (54).
Scheme 23: Addition of a stable (trifluoromethyl)zinc reagent to styrenes.
Scheme 24: The preparation of 2,2-difluorocyclopropanecarboxylic acids of type 58.
Scheme 25: Difluorocyclopropanation via Michael cyclization.
Scheme 26: Difluorocyclopropanation using N-acylimidazolidinone 60.
Scheme 27: Difluorocyclopropanation through the cyclization of phenylacetonitrile (61) and 1,2-dibromo-1,1-dif...
Scheme 28: gem-Difluoroolefins 64 for the synthesis of functionalized cyclopropanes 65.
Scheme 29: Preparation of aminocyclopropanes 70.
Scheme 30: Synthesis of fluorinated methylenecyclopropane 74 via selenoxide elimination.
Scheme 31: Reductive dehalogenation of (1R,3R)-75.
Scheme 32: Synthesis of chiral monoacetates by lipase catalysis.
Scheme 33: Transformation of (±)-trans-81 using Rhodococcus sp. AJ270.
Scheme 34: Transformation of (±)-trans-83 using Rhodococcus sp. AJ270.
Scheme 35: Hydrogenation of difluorocyclopropenes through enantioselective hydrocupration.
Scheme 36: Enantioselective transfer hydrogenation of difluorocyclopropenes with a Ru-based catalyst.
Scheme 37: The thermal transformation of trans-1,2-dichloro-3,3-difluorocyclopropane (84).
Scheme 38: cis–trans-Epimerization of 1,1-difluoro-2,3-dimethylcyclopropane.
Scheme 39: 2,2-Difluorotrimethylene diradical intermediate.
Scheme 40: Ring opening of stereoisomers 88 and 89.
Scheme 41: [1,3]-Rearrangement of alkenylcyclopropanes 90–92.
Scheme 42: Thermolytic rearrangement of 2,2-difluoro-1-vinylcyclopropane (90).
Scheme 43: Thermal rearrangement for ethyl 3-(2,2-difluoro)-3-phenylcyclopropyl)acrylates 93 and 95.
Scheme 44: Possible pathways of the ring opening of 1,1-difluoro-2-vinylcyclopropane.
Scheme 45: Equilibrium between 1,1-difluoro-2-methylenecyclopropane (96) and (difluoromethylene)cyclopropane 97...
Scheme 46: Ring opening of substituted 1,1-difluoro-2,2-dimethyl-3-methylenecyclopropane 98.
Scheme 47: 1,1-Difluorospiropentane rearrangement.
Scheme 48: Acetolysis of (2,2-difluorocyclopropyl)methyl tosylate (104) and (1,1-difluoro-2-methylcyclopropyl)...
Scheme 49: Ring opening of gem-difluorocyclopropyl ketones 106 and 108 by thiolate nucleophiles.
Scheme 50: Hydrolysis of gem-difluorocyclopropyl acetals 110.
Scheme 51: Ring-opening reaction of 2,2-difluorocyclopropyl ketones 113 in the presence of ionic liquid as a s...
Scheme 52: Ring opening of gem-difluorocyclopropyl ketones 113a by MgI2-initiated reaction with diarylimines 1...
Scheme 53: Ring-opening reaction of gem-difluorocyclopropylstannanes 117.
Scheme 54: Preparation of 1-fluorovinyl vinyl ketone 123 and the synthesis of 2-fluorocyclopentenone 124. TBAT...
Scheme 55: Iodine atom-transfer ring opening of 1,1-difluoro-2-(1-iodoalkyl)cyclopropanes 125a–c.
Scheme 56: Ring opening of bromomethyl gem-difluorocyclopropanes 130 and formation of gem-difluoromethylene-co...
Scheme 57: Ring-opening aerobic oxidation reaction of gem-difluorocyclopropanes 132.
Scheme 58: Dibrominative ring-opening functionalization of gem-difluorocyclopropanes 134.
Scheme 59: The selective formation of (E,E)- and (E,Z)-fluorodienals 136 and 137 from difluorocyclopropyl acet...
Scheme 60: Proposed mechanism for the reaction of difluoro(methylene)cyclopropane 139 with Br2.
Scheme 61: Thermal rearrangement of F2MCP 139 and iodine by CuI catalysis.
Scheme 62: Synthesis of 2-fluoropyrroles 142.
Scheme 63: Ring opening of gem-difluorocyclopropyl ketones 143 mediated by BX3.
Scheme 64: Lewis acid-promoted ring-opening reaction of 2,2-difluorocyclopropanecarbonyl chloride (148).
Scheme 65: Ring-opening reaction of the gem-difluorocyclopropyl ketone 106 by methanolic KOH.
Scheme 66: Hydrogenolysis of 1,1-difluoro-3-methyl-2-phenylcyclopropane (151).
Scheme 67: Synthesis of monofluoroalkenes 157.
Scheme 68: The stereoselective Ag-catalyzed defluorinative ring-opening diarylation of 1-trimethylsiloxy-2,2-d...
Scheme 69: Synthesis of 2-fluorinated allylic compounds 162.
Scheme 70: Pd-catalyzed cross-coupling reactions of gem-difluorinated cyclopropanes 161.
Scheme 71: The (Z)-selective Pd-catalyzed ring-opening sulfonylation of 2-(2,2-difluorocyclopropyl)naphthalene...
Figure 1: Structures of zosuquidar hydrochloride and PF-06700841.
Scheme 72: Synthesis of methylene-gem-difluorocyclopropane analogs of nucleosides.
Figure 2: Anthracene-difluorocyclopropane hybrid derivatives.
Figure 3: Further examples of difluorcyclopropanes in modern drug discovery.
Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans
- Viola Kolaříková,
- Markéta Rybáčková,
- Martin Svoboda and
- Jaroslav Kvíčala
Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226
- and the target products could not be identified (Scheme 13). To study the role of the electron density of the double bond, we also attempted the RCEYM of alkadiynyl acrylates 10 and alkadiynyl methacrylates 11. The lower reactivity of the double bond in these substrates led to negative results
- diynols 7b, 7c and 8b–d. Synthesis of the oxaenediynes 2 and 9 bearing an allyl or a methallyl group. Synthesis of oxaenediynes 2e and 2f bearing ester or silyl groups. Synthesis of alkadiynyl acrylates 10 and methacrylates 11. RCEYM of oxaenediynes 2. Attempted RCEYM of oxaenediynes 9, alkadiynyl
- acrylates 10 and methacrylates 11. Diels–Alder reaction of dihydropyran 12b with N-phenylmaleimide (13). Optimization of the catalyst loading depending on compound 2 triple bond substitution (NMR yields)a. RCEYM of oxaenediynes 2 (NMR yields). Supporting Information Supporting Information File 438
Graphical Abstract
Scheme 1: RCEYM with Ru and Mo catalysts.
Scheme 2: Beneficial effect of ethene atmosphere.
Scheme 3: Enantioselective dienyne metathesis [21].
Scheme 4: Diastereoselective endiyne metathesis [31].
Figure 1: Oxaenediynes considered for the study of desymmetrizing RCEYM.
Scheme 5: Synthesis of hepta-1,6-diyn-4-ol (4a).
Scheme 6: Protection of hepta-1,6-diyn-4-ol (4a).
Scheme 7: Alkylation of the protected diynols 7a and 8a.
Scheme 8: Deprotection of protected diynols 7b, 7c and 8b–d.
Scheme 9: Synthesis of the oxaenediynes 2 and 9 bearing an allyl or a methallyl group.
Scheme 10: Synthesis of oxaenediynes 2e and 2f bearing ester or silyl groups.
Scheme 11: Synthesis of alkadiynyl acrylates 10 and methacrylates 11.
Figure 2: The ruthenium precatalysts employed.
Scheme 12: RCEYM of oxaenediynes 2.
Figure 3: Examples of side products of CM with ethene.
Scheme 13: Attempted RCEYM of oxaenediynes 9, alkadiynyl acrylates 10 and methacrylates 11.
Scheme 14: Diels–Alder reaction of dihydropyran 12b with N-phenylmaleimide (13).
Figure 4: The four possible diastereoisomers of hexahydropyranoisoindole 14.
Figure 5: Conformations of dihydropyran 12b.
Figure 6: The two most stable s-trans (left) and s-cis (right) conformations of dihydropyran 12b.
Figure 7: The two most stable transition states endo-trans 15B and exo-cis 15C (hydrogens are omitted for cla...
Figure 8: PES of the Diels–Alder reaction of dihydropyran 12b and maleimide 13.
When metal-catalyzed C–H functionalization meets visible-light photocatalysis
- Lucas Guillemard and
- Joanna Wencel-Delord
Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147
- aromatic coupling partner, including frequently used Weinreb amides or functionalized secondary and primary amides. Regarding the scope of olefin substrates, the reaction tolerated numerous functional groups including acrylates, vinyl silanes or sulfones which was interesting from the post
Graphical Abstract
Figure 1: Concept of dual synergistic catalysis.
Figure 2: Classification of catalytic systems involving two catalysts.
Figure 3: General mechanism for the dual nickel/photoredox catalytic system.
Figure 4: General mechanisms for C–H activation catalysis involving different reoxidation strategies.
Figure 5: Indole synthesis via dual C–H activation/photoredox catalysis.
Figure 6: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 7: Oxidative Heck reaction on arenes via the dual catalysis.
Figure 8: Proposed mechanism for the Heck reaction on arenes via dual catalysis.
Figure 9: Oxidative Heck reaction on phenols via the dual catalysis.
Figure 10: Proposed mechanism for the Heck reaction on phenols via dual catalysis.
Figure 11: Carbazole synthesis via dual C–H activation/photoredox catalysis.
Figure 12: Proposed mechanism for the carbazole synthesis via dual catalysis.
Figure 13: Carbonylation of enamides via the dual C–H activation/photoredox catalysis.
Figure 14: Proposed mechanism for carbonylation of enamides via dual catalysis.
Figure 15: Annulation of benzamides via the dual C–H activation/photoredox catalysis.
Figure 16: Proposed mechanism for the annulation of benzamides via dual catalysis.
Figure 17: Synthesis of indoles via the dual C–H activation/photoredox catalysis.
Figure 18: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 19: General concept of dual catalysis merging C–H activation and photoredox catalysis.
Figure 20: The first example of dual catalysis merging C–H activation and photoredox catalysis.
Figure 21: Proposed mechanism for the C–H arylation with diazonium salts via dual catalysis.
Figure 22: Dual catalysis merging C–H activation/photoredox using diaryliodonium salts.
Figure 23: Direct arylation via the dual catalytic system reported by Xu.
Figure 24: Direct arylation via dual catalytic system reported by Balaraman.
Figure 25: Direct arylation via dual catalytic system reported by Guo.
Figure 26: C(sp3)–H bond arylation via the dual Pd/photoredox catalytic system.
Figure 27: Acetanilide derivatives acylation via the dual C–H activation/photoredox catalysis.
Figure 28: Proposed mechanism for the C–H acylation with α-ketoacids via dual catalysis.
Figure 29: Acylation of azobenzenes via the dual catalysis C–H activation/photoredox.
Figure 30: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 31: Proposed mechanism for the C2-acylation of indoles with aldehydes via dual catalysis.
Figure 32: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 33: Perfluoroalkylation of arenes via the dual C–H activation/photoredox catalysis.
Figure 34: Proposed mechanism for perfluoroalkylation of arenes via dual catalysis.
Figure 35: Sulfonylation of 1-naphthylamides via the dual C–H activation/photoredox catalysis.
Figure 36: Proposed mechanism for sulfonylation of 1-naphthylamides via dual catalysis.
Figure 37: meta-C–H Alkylation of arenes via visible-light metallaphotocatalysis.
Figure 38: Alternative procedure for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 39: Proposed mechanism for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 40: C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 41: Proposed mechanism for C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 42: Undirected C–H aryl–aryl cross coupling via dual gold/photoredox catalysis.
Figure 43: Proposed mechanism for the undirected C–H aryl–aryl cross-coupling via dual catalysis.
Figure 44: Undirected C–H arylation of (hetero)arenes via dual manganese/photoredox catalysis.
Figure 45: Proposed mechanism for the undirected arylation of (hetero)arenes via dual catalysis.
Figure 46: Photoinduced C–H arylation of azoles via copper catalysis.
Figure 47: Photo-induced C–H chalcogenation of azoles via copper catalysis.
Figure 48: Decarboxylative C–H adamantylation of azoles via dual cobalt/photoredox catalysis.
Figure 49: Proposed mechanism for the C–H adamantylation of azoles via dual catalysis.
Figure 50: General mechanisms for the “classical” (left) and Cu-free variant (right) Sonogoshira reaction.
Figure 51: First example of a dual palladium/photoredox catalysis for Sonogashira-type couplings.
Figure 52: Arylation of terminal alkynes with diazonium salts via dual gold/photoredox catalysis.
Figure 53: Proposed mechanism for the arylation of terminal alkynes via dual catalysis.
Figure 54: C–H Alkylation of alcohols promoted by H-atom transfer (HAT).
Figure 55: Proposed mechanism for the C–H alkylation of alcohols promoted by HAT.
Figure 56: C(sp3)–H arylation of latent nucleophiles promoted by H-atom transfer.
Figure 57: Proposed mechanism for the C(sp3)–H arylation of latent nucleophiles promoted by HAT.
Figure 58: Direct α-arylation of alcohols promoted by H-atom transfer.
Figure 59: Proposed mechanism for the direct α-arylation of alcohols promoted by HAT.
Figure 60: C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 61: Proposed mechanism for the C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 62: C–H functionalization of nucleophiles via excited ketone/nickel dual catalysis.
Figure 63: Proposed mechanism for the C–H functionalization enabled by excited ketones.
Figure 64: Selective sp3–sp3 cross-coupling promoted by H-atom transfer.
Figure 65: Proposed mechanism for the selective sp3–sp3 cross-coupling promoted by HAT.
Figure 66: Direct C(sp3)–H acylation of amines via dual Ni/photoredox catalysis.
Figure 67: Proposed mechanism for the C–H acylation of amines via dual Ni/photoredox catalysis.
Figure 68: C–H hydroalkylation of internal alkynes via dual Ni/photoredox catalysis.
Figure 69: Proposed mechanism for the C–H hydroalkylation of internal alkynes.
Figure 70: Alternative procedure for the C–H hydroalkylation of ynones, ynoates, and ynamides.
Figure 71: Allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 72: Proposed mechanism for the allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 73: Asymmetric allylation of aldehydes via dual Cr/photoredox catalysis.
Figure 74: Proposed mechanism for the asymmetric allylation of aldehydes via dual catalysis.
Figure 75: Aldehyde C–H functionalization promoted by H-atom transfer.
Figure 76: Proposed mechanism for the C–H functionalization of aldehydes promoted by HAT.
Figure 77: Direct C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 78: Proposed mechanism for the C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 79: Direct C–H trifluoromethylation of strong aliphatic bonds promoted by HAT.
Figure 80: Proposed mechanism for the C–H trifluoromethylation of strong aliphatic bonds.
Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole
- Carlos H. Escalante,
- Eder I. Martínez-Mora,
- Carlos Espinoza-Hicks,
- Alejandro A. Camacho-Dávila,
- Fernando R. Ramos-Morales,
- Francisco Delgado and
- Joaquín Tamariz
Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113
- - and pyrrolo-fused polycyclic indoles is herein described, starting from 2-formylpyrrole and employing Diels–Alder and Heck arylation reactions. 3-(N-Benzyl-2-pyrrolyl)acrylates and 4-(pyrrol-2-yl)butenones underwent a highly endo-Diels–Alder cycloaddition with maleimides to furnish octahydropyrrolo
- [3,4-e]indoles, which served as precursors in the regioselective synthesis of aza-polycyclic skeletons via an intramolecular Heck arylation reaction. Through the latter reaction, the 3-(N-benzyl-2-pyrrolyl)acrylates give rise to 3-(pyrrolo[2,1-a]isoindol-3-yl)acrylates. A further oxidative
- base (Table 1, entries 7 and 8). The second methodology consisted of an inverted sequence of reactions in relation to the previous approach, starting from the treatment of 13a with 15a,b to give 3-(pyrrol-2-yl)acrylates 16a–b (Scheme 2). The latter compounds were alkylated with allyl bromide (14e) and
Graphical Abstract
Figure 1: Fused aza-hetero polycyclic frames and natural pyrrolizine- and isoindole-containing alkaloids.
Scheme 1: Synthetic approaches for the preparation of pyrrolo-fused aza-hetero polycyclic frames.
Scheme 2: Preparation of 1,2-substituted pyrroles 8a–f and 8i,j.
Scheme 3: Diels–Alder cycloadditions of pyrroles 8a–j and 16a–b with maleimides 7b–c.
Figure 2: Structures of 9m (a) and 10m (b) as determined by single-crystal X-ray diffraction crystallography ...
Scheme 4: Pd(0)-catalyzed intramolecular Heck cross-coupling reaction of 2-vinylpyrroles 8c,d and 8g.
Scheme 5: Synthesis of 2-vinylpyrroles 8k,l and their Pd(0)-catalyzed intramolecular Heck cross-coupling to p...
Scheme 6: Diastereoselective Diels–Alder reaction of pyrrolo[2,1-a]isoindole 18a with 7c.
Scheme 7: Synthetic approach to the fused aza-heterocyclic pentacycle 12.
Figure 3: M06-2X/6-31+G(d,p) Optimized geometry for each of the SCs (a and d), TSs (b and e) and ADs (c and f...
Figure 4: M06-2X/6-31+G(d,p) Optimized geometry for each of the TSs of the Diels–Alder reactions of dienes 8b...
Figure 5: M06-2X/6-31+G(d,p) Optimized geometry of the endo SCs (a) and TSs (b) for the Diels–Alder reaction ...
Aldehydes as powerful initiators for photochemical transformations
- Maria A. Theodoropoulou,
- Nikolaos F. Nikitas and
- Christoforos G. Kokotos
Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76
- -one, as well as formaldehyde (35), efficiently initiated the polymerization of MAA (42), and butanone was the most efficient compound. Since acrylates and methacrylates can be photopolymerized by self-initiation, a blank experiment without the use of any aliphatic ketone 44 or formaldehyde (35) was
Graphical Abstract
Scheme 1: Norrish type I and II dissociations.
Scheme 2: Proposed radical pair formation after the photolysis of benzaldehyde (8).
Scheme 3: Aldehydes in the Paterno–Büchi reaction.
Scheme 4: 2,3-Diazabicyclo[2.2.1]hept-2-ene (DBH).
Scheme 5: Dissociation pathways of benzaldehyde.
Scheme 6: Reactions that lead to polarized products detectable by CIDNP.
Scheme 7: MMA (26), DEABP (27), and Michler’s ketone (28).
Scheme 8: Radical intermediates of DEABP.
Scheme 9: Photoinitiated polymerization of monomeric MMA (26) using the quinoxalines 32 and benzaldehyde (8).
Scheme 10: Acetone (4) and formaldehyde (35) as photografting initiators.
Scheme 11: Photografting by employing acetaldehyde (36) as the photoinitiator.
Scheme 12: Proposed photolysis mechanism for aliphatic ketones 44 and formaldehyde (35).
Scheme 13: Initiator 50, reductant 51, and benzaldehyde derivatives 52–54 for the polymerization of the methac...
Scheme 14: Proposed mechanism of the photomediated atom transfer radical polymerization employing the benzalde...
Scheme 15: cis/trans isomerization employing triplet states of photosensitizers.
Scheme 16: Salicylaldehyde (68) forms an internal hydrogen bond.
Scheme 17: Olefin isomerization via energy transfer from a carbonyl compound.
Scheme 18: Mechanistic pathways for the Paterno–Büchi reaction.
Scheme 19: Isomeric oxetanes formed after photochemical addition of aryl aldehydes to 2-butenes.
Scheme 20: Rotation of the C3–C4 bond of the biradical intermediate may lead to all four conformations.
Scheme 21: Photolysis products of benzaldehyde (8) in different solvents. a) In benzene or ethanol. b) In hex-...
Scheme 22: N-tert-Butylbenzamide formation proceeds via a benzoyl radical.
Scheme 23: Photochemical pinacol coupling.
Scheme 24: Photochemical ATRA catalyzed by 4-anisaldehyde (52).
Scheme 25: Proposed triplet sensitization mechanism of the ATRA reaction in the presence of 4-anisaldehyde (52...
Scheme 26: Benzaldehyde-mediated photoredox CDC reaction: compatible amides and ethers.
Scheme 27: Photoredox cross-dehydrogenative coupling (CDC) conditions and proposed reaction mechanism.
Scheme 28: Optimized conditions for the photoredox merger reaction.
Scheme 29: Proposed mechanism for the C(sp3)–H alkylation/arylation of ethers.
Scheme 30: Substrate scope for the photochemical alkylation of ethers.
Scheme 31: C(sp3)–H Functionalization of N-containing molecules.
Scheme 32: Substrate scope for the photochemical alkylation of N-containing molecules.
Scheme 33: Additional products yielded by the photochemical alkylation reaction of N-containing molecules.
Scheme 34: C(sp3)–H functionalization of thioethers.
Scheme 35: Proposed mechanism for the C(sp3)–H alkylation/arylation of N-containing molecules and thioethers.
Scheme 36: Hydroacylation using 4-cyanobenzaldehyde (53) as the photoinitiator.
Scheme 37: Selectivity for the formation of the α,α-disubstituted aldehydes.
Scheme 38: Substrate scope for the photochemical addition of aldehydes to Michael acceptors.
Scheme 39: Proposed mechanism for the hydroacylation of Michael acceptors using 4-cyanobenzaldehyde (53) as th...
Scheme 40: Catalytic arylation of aromatic aldehydes by aryl bromides in which the reaction product acts as th...
Scheme 41: Proposed mechanism for the catalytic arylation of benzaldehydes by aryl bromides in which the react...
Scheme 42: Functionalization of the chiral cyclobutanes 180.
Scheme 43: Optimized reaction conditions and proposed mechanism for the sulfonylcyanation of cyclobutenes.
Recent advances in Cu-catalyzed C(sp3)–Si and C(sp3)–B bond formation
- Balaram S. Takale,
- Ruchita R. Thakore,
- Elham Etemadi-Davan and
- Bruce H. Lipshutz
Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67
- intermediate. This species then undergoes [3,3]-sigmatropic rearrangement, positioning the allylic unit in a regio- and stereospecific manner, along with rearomatization to afford the products 357–360 (Scheme 57) [107]. The borylfluoromethylation of acrylamides, acrylates, and heteroaromatic-substituted alkenes
Graphical Abstract
Scheme 1: Pharmaceuticals possessing a silicon or boron atom.
Scheme 2: The first Cu-catalyzed C(sp3)–Si bond formation.
Scheme 3: Conversion of benzylic phosphate 6 to the corresponding silane.
Scheme 4: Conversion of alkyl triflates to alkylsilanes.
Scheme 5: Conversion of secondary alkyl triflates to alkylsilanes.
Scheme 6: Conversion of alkyl iodides to alkylsilanes.
Scheme 7: Trapping of intermediate radical through cascade reaction.
Scheme 8: Radical pathway for conversion of alkyl iodides to alkylsilanes.
Scheme 9: Conversion of alkyl ester of N-hydroxyphthalimide to alkylsilanes.
Scheme 10: Conversion of gem-dibromides to bis-silylalkanes.
Scheme 11: Conversion of imines to α-silylated amines (A) and the reaction pathway (B).
Scheme 12: Conversion of N-tosylimines to α-silylated amines.
Scheme 13: Screening of diamine ligands.
Scheme 14: Conversion of N-tert-butylsulfonylimines to α-silylated amines.
Scheme 15: Conversion of aldimines to nonracemic α-silylated amines.
Scheme 16: Conversion of N-tosylimines to α-silylated amines.
Scheme 17: Reaction pathway [A] and conversion of aldehydes to α-silylated alcohols [B].
Scheme 18: Conversion of aldehydes to benzhydryl silyl ethers.
Scheme 19: Conversion of ketones to 1,2-diols (A) and conversion of imines to 1,2-amino alcohols (B).
Scheme 20: Ligand screening (A) and conversion of aldehydes to α-silylated alcohols (B).
Scheme 21: Conversion of aldehydes to α-silylated alcohols.
Scheme 22: 1,4-Additions to α,β-unsaturated ketones.
Scheme 23: 1,4-Additions to unsaturated ketones to give β-silylated derivatives.
Scheme 24: Additions onto α,β-unsaturated lactones to give β-silylated lactones.
Scheme 25: Conversion of α,β-unsaturated to β-silylated lactams.
Scheme 26: Conversion of N-arylacrylamides to silylated oxindoles.
Scheme 27: Conversion of α,β-unsaturated carbonyl compounds to silylated tert-butylperoxides.
Scheme 28: Catalytic cycle for Cu(I) catalyzed α,β-unsaturated compounds.
Scheme 29: Conversion of p-quinone methides to benzylic silanes.
Scheme 30: Conversion of α,β-unsaturated ketimines to regio- and stereocontrolled allylic silanes.
Scheme 31: Conversion of α,β-unsaturated ketimines to enantioenriched allylic silanes.
Scheme 32: Regioselective conversion of dienedioates to allylic silanes.
Scheme 33: Conversion of alkenyl-substituted azaarenes to β-silylated adducts.
Scheme 34: Conversion of conjugated benzoxazoles to enantioenriched β-silylated adducts.
Scheme 35: Conversion of α,β-unsaturated carbonyl indoles to α-silylated N-alkylated indoles.
Scheme 36: Conversion of β-amidoacrylates to α-aminosilanes.
Scheme 37: Conversion of α,β-unsaturated ketones to enantioenriched β-silylated ketones, nitriles, and nitro d...
Scheme 38: Regio-divergent silacarboxylation of allenes.
Scheme 39: Silylation of diazocarbonyl compounds, (A) asymmetric and (B) racemic.
Scheme 40: Enantioselective hydrosilylation of alkenes.
Scheme 41: Conversion of 3-acylindoles to indolino-silanes.
Scheme 42: Proposed mechanism for the silylation of 3-acylindoles.
Scheme 43: Silyation of N-chlorosulfonamides.
Scheme 44: Conversion of acyl silanes to α-silyl alcohols.
Scheme 45: Conversion of N-tosylaziridines to β-silylated N-tosylamines.
Scheme 46: Conversion of N-tosylaziridines to silylated N-tosylamines.
Scheme 47: Conversion of 3,3-disubstituted cyclopropenes to silylated cyclopropanes.
Scheme 48: Conversion of conjugated enynes to 1,3-bis(silyl)propenes.
Scheme 49: Proposed sequence for the Cu-catalyzed borylation of substituted alkenes.
Scheme 50: Cu-catalyzed synthesis of nonracemic allylic boronates.
Scheme 51: Cu–NHC catalyzed synthesis of α-substituted allylboronates.
Scheme 52: Synthesis of α-chiral (γ-alkoxyallyl)boronates.
Scheme 53: Cu-mediated formation of nonracemic cis- or trans- 2-substituted cyclopropylboronates.
Scheme 54: Cu-catalyzed synthesis of γ,γ-gem-difluoroallylboronates.
Scheme 55: Cu-catalyzed hydrofunctionalization of internal alkenes and vinylarenes.
Scheme 56: Cu-catalyzed Markovnikov and anti-Markovnikov borylation of alkenes.
Scheme 57: Cu-catalyzed borylation/ortho-cyanation/Cope rearrangement.
Scheme 58: Borylfluoromethylation of alkenes.
Scheme 59: Cu-catalyzed synthesis of tertiary nonracemic alcohols.
Scheme 60: Synthesis of densely functionalized and synthetically versatile 1,2- or 4,3-borocyanated 1,3-butadi...
Scheme 61: Cu-catalyzed trifunctionalization of allenes.
Scheme 62: Cu-catalyzed selective arylborylation of arenes.
Scheme 63: Asymmetric borylative coupling between styrenes and imines.
Scheme 64: Regio-divergent aminoboration of unactivated terminal alkenes.
Scheme 65: Cu-catalyzed 1,4-borylation of α,β-unsaturated ketones.
Scheme 66: Cu-catalyzed protodeboronation of α,β-unsaturated ketones.
Scheme 67: Cu-catalyzed β-borylation of α,β-unsaturated imines.
Scheme 68: Cu-catalyzed synthesis of β-trifluoroborato carbonyl compounds.
Scheme 69: Asymmetric 1,4-borylation of α,β-unsaturated carbonyl compounds.
Scheme 70: Cu-catalyzed ACB and ACA reactions of α,β-unsaturated 2-acyl-N-methylimidazoles.
Scheme 71: Cu-catalyzed diborylation of aldehydes.
Scheme 72: Umpolung pathway for chiral, nonracemic tertiary alcohol synthesis (top) and proposed mechanism for...
Scheme 73: Cu-catalyzed synthesis of α-hydroxyboronates.
Scheme 74: Cu-catalyzed borylation of ketones.
Scheme 75: Cu-catalyzed borylation of unactivated alkyl halides.
Scheme 76: Cu-catalyzed borylation of allylic difluorides.
Scheme 77: Cu-catalyzed borylation of cyclic and acyclic alkyl halides.
Scheme 78: Cu-catalyzed borylation of unactivated alkyl chlorides and bromides.
Scheme 79: Cu-catalyzed decarboxylative borylation of carboxylic acids.
Scheme 80: Cu-catalyzed borylation of benzylic, allylic, and propargylic alcohols.
Recent advances in photocatalyzed reactions using well-defined copper(I) complexes
- Mingbing Zhong,
- Xavier Pannecoucke,
- Philippe Jubault and
- Thomas Poisson
Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42
- , acrylates, enol acetates, and enamines. The functional group tolerance of the transformation was fairly decent and demonstrated the synthetic utility of this reaction manifold. To explain the reaction outcome, the authors suggested the following mechanism: The excited copper catalyst reduces the CF3SO2Cl
Graphical Abstract
Scheme 1: [Cu(I)(dap)2]Cl-catalyzed ATRA reaction under green light irradiation.
Scheme 2: Photocatalytic allylation of α-haloketones.
Scheme 3: [Cu(I)(dap)2]Cl-photocatalyzed chlorosulfonylation and chlorotrifluoromethylation of alkenes.
Scheme 4: Photocatalytic perfluoroalkylchlorination of electron-deficient alkenes using the Sauvage catalyst.
Scheme 5: Photocatalytic synthesis of fluorinated sultones.
Scheme 6: Photocatalyzed haloperfluoroalkylation of alkenes and alkynes.
Scheme 7: Chlorosulfonylation of alkenes catalyzed by [Cu(I)(dap)2]Cl. aNo Na2CO3 was added. b1 equiv of Na2CO...
Scheme 8: Copper-photocatalyzed reductive allylation of diaryliodonium salts.
Scheme 9: Copper-photocatalyzed azidomethoxylation of olefins.
Scheme 10: Benzylic azidation initiated by [Cu(I)(dap)2]Cl.
Scheme 11: Trifluoromethyl methoxylation of styryl derivatives using [Cu(I)(dap)2]PF6. All redox potentials ar...
Scheme 12: Trifluoromethylation of silyl enol ethers.
Scheme 13: Synthesis of annulated heterocycles upon oxidation with the Sauvage catalyst.
Scheme 14: Oxoazidation of styrene derivatives using [Cu(dap)2]Cl as a precatalyst.
Scheme 15: [Cu(I)(dpp)(binc)]PF6-catalyzed ATRA reaction.
Scheme 16: Allylation reaction of α-bromomalonate catalyzed by [Cu(I)(dpp)(binc)]PF6 following an ATRA mechani...
Scheme 17: Bromo/tribromomethylation reaction using [Cu(I)(dmp)(BINAP)]PF6.
Scheme 18: Chlorotrifluoromethylation of alkenes catalyzed by [Cu(I)(N^N)(xantphos)]PF6.
Scheme 19: Chlorosulfonylation of styrene and alkyne derivatives by ATRA reactions.
Scheme 20: Reduction of aryl and alkyl halides with the complex [Cu(I)(bcp)(DPEPhos)]PF6. aIrradiation was car...
Scheme 21: Meerwein arylation of electron-rich aromatic derivatives and 5-exo-trig cyclization catalyzed by th...
Scheme 22: [Cu(I)(bcp)(DPEPhos)]PF6-photocatalyzed synthesis of alkaloids. aYield over two steps (cyclization ...
Scheme 23: Copper-photocatalyzed decarboxylative amination of NHP esters.
Scheme 24: Photocatalytic decarboxylative alkynylation using [Cu(I)(dq)(binap)]BF4.
Scheme 25: Copper-photocatalyzed alkylation of glycine esters.
Scheme 26: Copper-photocatalyzed borylation of organic halides. aUnder continuous flow conditions.
Scheme 27: Copper-photocatalyzed α-functionalization of alcohols with glycine ester derivatives.
Scheme 28: δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4.
Scheme 29: Photocatalytic synthesis of [5]helicene and phenanthrene.
Scheme 30: Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4.
Scheme 31: Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines.
Scheme 32: Bicyclic lactone synthesis using a copper-photocatalyzed PCET reaction.
Scheme 33: Photocatalytic Pinacol coupling reaction catalyzed by [Cu(I)(pypzs)(BINAP)]BF4. The ligands of the ...
Scheme 34: Azide photosensitization using a Cu-based photocatalyst.
Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0
- Bernd Strehmel,
- Christian Schmitz,
- Ceren Kütahya,
- Yulian Pang,
- Anke Drewitz and
- Heinz Mustroph
Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40
- ]. Such a geometry affects compatibility with the surrounding matrix. Thus, aggregation phenomena dominate in the case of IV. On the other hand, absorbers related to V often exhibit a much better solubility in organic surroundings such as multi-functional acrylates [5]. This can be seen as a huge
- surroundings is the biggest challenge in practical applications of these systems. Thus, counter ions such as n-C12H25-Ph-SO3− (8, 10, 79, 81), NTf2− (4) or [Al(OC4F9)4]− (37) depict alternatives resulting in a solubility of 10–30 g/L in reactive monomers such as multifunctional acrylates [5], printing inks or
- coating, where they properly helped to melt and cure the applied powder monomers nearly just in one step [16]. Typical monomers used in CtP, liquid coatings and powder coatings derive from urethane (meth)acrylates, epoxy (meth)acrylates, polyester(meth)acrylates or polyether (meth)acrylates. Literature
Graphical Abstract
Scheme 1: Structural patterns of several symmetric cyanines relating to trimethines (I), pentamethines (II), ...
Scheme 2: 1-Substituted 2,3,3-trimethylindolium-, 2,3,3-benzo[e]indolium-, and 2,3,3-benzo[c,d]indolium salts...
Scheme 3: Substitution of the chlorine substituent at the meso-position by a stronger nucleophilic moiety B [68].
Scheme 4: Structure of alternative chain builders for synthesis of heptamethines.
Figure 1: Simplified process chart of photophysical processes occurring in NIR absorbers.
Scheme 5: Chemical structure of the electron acceptors that were from iodonium cations 88 and triazines 89.
Figure 2: Photoinduced electron transfer under different scenarios in which each example exhibits an intrinsi...
Scheme 6: Photoexcited absorber 33 results in reaction with an iodonium cation in the respective cation radic...
Scheme 7: Reaction scheme of absorbers comprising in the molecules center a five ring bridged moiety. This le...
Scheme 8: Structure of donor compounds used in a three component system.
Figure 3: Cationic photopolymerization of an epoxide (Epikote 828) initiated by excitation of the absorber 36...
Scheme 9: Different modes of photoinitiated ATRP using UV, visible and NIR light.
Scheme 10: The structure of Sens used in photo-ATRP.
Figure 4: Comparison of the GPC traces of precursor PMMA with a) chain extended PMMA and b) PMMA-b-PS. Condit...
Figure 5: Spectral changes of the solution of 48 in the presence of [Cu(L)]Br2 (L: tris(2-pyridylmethyl)amine...
Scheme 11: Photoinduced CuAAC reactions in which photochemical reactions result in formation of the Cu(I) cata...
Scheme 12: Model reaction between benzyl azide and phenyacetylene using the absorber 48 as NIR sensitizer at 7...
Figure 6: Block copolymerization of the precursors PS-N3 and Alkyne-PCL results in the block copolymer PS-b-P...
Figure 7: UV–vis–NIR absorption changes of the solution of 48 in the presence of PMDETA, phenylacetylene and ...
Scheme 13: Workflow to design and process new materials in a setup based on an intelligent DoE to develop tech...
Scheme 14: Illustration of the iDoE setting up experiments suggested and analyzed by the A.I. After defining t...
Scheme 15: Classification of the factors for the formation of polymer networks by NIR-photocuring depending on...
Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst
- Abhijit Paul,
- Debnath Chatterjee,
- Srirupa Banerjee and
- Somnath Yadav
Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16
- reaction was also carried out using [Ru(p-cymene)Cl2]2 as a homogeneous catalyst, but this also did not lead to the formation of the desired product. After establishing the optimum conditions for the reaction, we carried out the alkenylation of several indole derivatives 1 with different acrylates 2 under
Graphical Abstract
Figure 1: Biologically and medicinally important 3-alkenylindoles.
Scheme 1: a) Previous and b) present work related to the synthesis of 3-alkenylindoles.
Scheme 2: Substrate scope for the C–H alkenylation of the indoles 1. Reaction conditions: 1 (1 mmol), 2 (2 mm...
Scheme 3: a) Three-phase test to determine a homogeneous or heterogeneous catalytic mechanism of action for t...
Scheme 4: Probable catalytic mechanism for the transformation of 1a by the RuNC.
Functionalization of the imidazo[1,2-a]pyridine ring in α-phosphonoacrylates and α-phosphonopropionates via microwave-assisted Mizoroki–Heck reaction
- Damian Kusy,
- Agata Wojciechowska,
- Joanna Małolepsza and
- Katarzyna M. Błażewska
Beilstein J. Org. Chem. 2020, 16, 15–21, doi:10.3762/bjoc.16.3
- -bromoimidazo[1,2-a]pyridin-3-yl)-2-(diethoxyphosphoryl)acrylates 1, no desired product 3 was formed under standard heating conditions (Table 1, entry 1). Recently, multiple variants for the application of microwave heating for conducting Mizoroki–Heck reactions have been reported, including the use of
- )acrylate (analogs 1) or 2-(diethoxyphosphoryl)propanoates (analogs 2). The reaction worked well for a number of acrylates (Scheme 1), providing predominantly products with (E)-geometry of the newly formed double bond (E/Z ratio is above 98:2). Only for analog 11, the formation of the (Z)-product was
- -(bromoimidazo[1,2-a]pyridin-3-yl)-2-(diethoxyphosphoryl)acrylates 1 and propionates 2 using microwave-assisted Mizoroki–Heck reaction. The method worked for a number of olefins, enabling the functionalization of the heterocyclic ring with diverse groups, which can be used for further modifications. Importantly
Graphical Abstract
Figure 1: Substrates used for the Mizoroki–Heck reaction in this study.
Figure 2: Structures of the identified side products 4 and 5.
Scheme 1: Scope of the method for analogs derived from 1 and 2. The ratio of isomers is given (E/Z or β/α) in...
Scheme 2: Dealkylation of fluorinated analog 23 under the Mizoroki–Heck reaction conditions.
N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds
- Iwona E. Głowacka,
- Aleksandra Trocha,
- Andrzej E. Wróblewski and
- Dorota G. Piotrowska
Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168
- peptidyl nucleosides with primarily antifungal properties. The stereoselective synthesis of (+)-polyoxamic acid ((2S,3S,4S)-144) was successfully carried out starting with Horner–Wadsworth–Emmons olefination of the aziridine aldehyde (2R,1'R)-6 which provided a 98:2 mixture of trans- and cis-acrylates 69b
Graphical Abstract
Figure 1: Examples of three-carbon chirons.
Figure 2: Structures of derivatives of N-(1-phenylethyl)aziridine-2-carboxylic acid 5–8.
Figure 3: Synthetic equivalency of aziridine aldehydes 6.
Scheme 1: Synthesis of N-(1-phenylethyl)aziridine-2-carboxylates 5. Reagents and conditions: a) TEA, toluene,...
Scheme 2: Absolute configuration at C2 in (2S,1'S)-5a. Reagents and conditions: a) 20% HClO4, 80 °C, 30 h the...
Scheme 3: Major synthetic strategies for a 2-ketoaziridine scaffold [R* = (R)- or (S)-1-phenylethyl; R′ = Alk...
Scheme 4: Synthesis of cyanide (2S,1'S)-13. Reagents and conditions: a) NH3, EtOH/H2O, rt, 72 h; b) Ph3P, CCl4...
Scheme 5: Synthesis of key intermediates (R)-16 and (R)-17 for (R,R)-formoterol (14) and (R)-tamsulosin (15)....
Scheme 6: Synthesis of mitotic kinesin inhibitors (2R/S,1'R)-23. Reagents and conditions: a) H2, Pd(OH)2, EtO...
Scheme 7: Synthesis of (R)-mexiletine ((R)-24). Reagents and conditions: a) TsCl, TEA, DMAP, CH2Cl2, rt, 1 h;...
Scheme 8: Synthesis of (−)-cathinone ((S)-27). Reagents and conditions: a) PhMgBr, ether, 0 °C; b) H2, 10% Pd...
Scheme 9: Synthesis of N-Boc-norpseudoephedrine ((1S,2S)-(+)-29) and N-Boc-norephedrine ((1R,2S)-29). Reagent...
Scheme 10: Synthesis of (−)-ephedrine ((1R,2S)-31). Reagents and conditions: a) TfOMe, MeCN then NaBH3CN, rt; ...
Scheme 11: Synthesis of xestoaminol C ((2S,3R)-35), 3-epi-xestoaminol C ((2S,3S)-35) and N-Boc-spisulosine ((2S...
Scheme 12: Synthesis of ʟ-tryptophanol ((S)-41). Reagents and conditions: a) CDI, MeCN, rt, 1 h then TMSI, MeC...
Scheme 13: Synthesis of ʟ-homophenylalaninol ((S)-42). Reagents and conditions: a) NaH, THF, 0 °C to −78 °C, 1...
Scheme 14: Synthesis of ᴅ-homo(4-octylphenyl)alaninol ((R)-47) and a sphingolipid analogue (R)-48. Reagents an...
Scheme 15: Synthesis of florfenicol ((1R,2S)-49). Reagents and conditions: a) (S)-1-phenylethylamine, TEA, MeO...
Scheme 16: Synthesis of natural tyroscherin ((2S,3R,6E,8R,10R)-55). Reagents and conditions: a) I(CH2)3OTIPS, t...
Scheme 17: Syntheses of (−)-hygrine (S)-61, (−)-hygroline (2S,2'S)-62 and (−)-pseudohygroline (2S,2'R)-62. Rea...
Scheme 18: Synthesis of pyrrolidine (3S,3'R)-68, a fragment of the fluoroquinolone antibiotic PF-00951966. Rea...
Scheme 19: Synthesis of sphingolipid analogues (R)-76. Reagents and conditions: a) BnBr, Mg, THF, reflux, 6 h;...
Scheme 20: Synthesis of ᴅ-threo-PDMP (1R,2R)-81. Reagents and conditions: a) TMSCl, NaI, MeCN, rt, 1 h 50 min,...
Scheme 21: Synthesis of the sphingolipid analogue SG-14 (2S,3S)-84. Reagents and conditions: a) LiAlH4, THF, 0...
Scheme 22: Synthesis of the sphingolipid analogue SG-12 (2S,3R)-88. Reagents and conditions: a) 1-(bromomethyl...
Scheme 23: Synthesis of sphingosine-1-phosphate analogues DS-SG-44 and DS-SG-45 (2S,3R)-89a and (2S,3R)-89a. R...
Scheme 24: Synthesis of N-Boc-safingol ((2S,3S)-95) and N-Boc-ᴅ-erythro-sphinganine ((2S,3R)-95). Reagents and...
Scheme 25: Synthesis of ceramide analogues (2S,3R)-96. Reagents and conditions: a) NaBH4, ZnCl2, MeOH, −78 °C,...
Scheme 26: Synthesis of orthogonally protected serinols, (S)-101 and (R)-102. Reagents and conditions: a) BnBr...
Scheme 27: Synthesis of N-acetyl-3-phenylserinol ((1R,2R)-105). Reagents and conditions: a) AcOH, CH2Cl2, refl...
Scheme 28: Synthesis of (S)-linezolid (S)-107. Reagents and conditions: a) LiAlH4, THF, 0 °C to reflux; b) Boc2...
Scheme 29: Synthesis of (2S,3S,4R)-2-aminooctadecane-1,3,4-triol (ᴅ-ribo-phytosphingosine) (2S,3S,4R)-110. Rea...
Scheme 30: Syntheses of ᴅ-phenylalanine (R)-116. Reagents and conditions: a) AcOH, CH2Cl2, reflux, 4 h; b) MsC...
Scheme 31: Synthesis of N-Boc-ᴅ-3,3-diphenylalanine ((R)-122). Reagents and conditions: a) PhMgBr, THF, −78 °C...
Scheme 32: Synthesis of ethyl N,N’-di-Boc-ʟ-2,3-diaminopropanoate ((S)-125). Reagents and conditions: a) NaN3,...
Scheme 33: Synthesis of the bicyclic amino acid (S)-(+)-127. Reagents and conditions: a) BF3·OEt2, THF, 60 °C,...
Scheme 34: Synthesis of lacosamide, (R)-2-acetamido-N-benzyl-3-methoxypropanamide (R)-130. Reagents and condit...
Scheme 35: Synthesis of N-Boc-norfuranomycin ((2S,2'R)-133). Reagents and conditions: a) H2C=CHCH2I, NaH, THF,...
Scheme 36: Synthesis of MeBmt (2S,3R,4R,6E)-139. Reagents and conditions: a) diisopropyl (S,S)-tartrate (E)-cr...
Scheme 37: Synthesis of (+)-polyoxamic acid (2S,3S,4S)-144. Reagents and conditions: a) AD-mix-α, MeSO2NH2, t-...
Scheme 38: Synthesis of the protected 3-hydroxy-ʟ-glutamic acid (2S,3R)-148. Reagents and conditions: a) LiHMD...
Scheme 39: Synthesis of (+)-isoserine (R)-152. Reagents and conditions: a) AcCl, MeCN, rt, 0.5 h then Na2CO3, ...
Scheme 40: Synthesis of (3R,4S)-N3-Boc-3,4-diaminopentanoic acid (3R,4S)-155. Reagents and conditions: a) Ph3P...
Scheme 41: Synthesis of methyl (2S,3S,4S)-4-(dimethylamino)-2,3-dihydroxy-5-methoxypentanoate (2S,3S,4S)-159. ...
Scheme 42: Syntheses of methyl (3S,4S) 4,5-di-N-Boc-amino-3-hydroxypentanoate ((3S,4S)-164), methyl (3S,4S)-4-N...
Scheme 43: Syntheses of (3R,5S)-5-(aminomethyl)-3-(4-methoxyphenyl)dihydrofuran-2(3H)-one ((3R,5S)-168). Reage...
Scheme 44: Syntheses of a series of imidazolin-2-one dipeptides 175–177 (for R' and R'' see text). Reagents an...
Scheme 45: Syntheses of (2S,3S)-N-Boc-3-hydroxy-2-hydroxymethylpyrrolidine ((2S,3S)-179). Reagents and conditi...
Scheme 46: Syntheses of enantiomers of 1,4-dideoxy-1,4-imino-ʟ- and -ᴅ-lyxitols (2S,3R,4S)-182 and (2R,3S,4R)-...
Scheme 47: Synthesis of 1,4-dideoxy-1,4-imino-ʟ-ribitol (2S,3S,4R)-182. Reagents and conditions: a) AcOH, CH2Cl...
Scheme 48: Syntheses of 1,4-dideoxy-1,4-imino-ᴅ-arabinitol (2R,3R,4R)-182 and 1,4-dideoxy-1,4-imino-ᴅ-xylitol ...
Scheme 49: Syntheses of natural 2,5-imino-2,5,6-trideoxy-ʟ-gulo-heptitol ((2S,3R,4R,5R)-184) and its C4 epimer...
Scheme 50: Syntheses of (−)-dihydropinidine ((2S,6R)-187a) (R = C3H7) and (2S,6R)-isosolenopsins (2S,6R)-187b ...
Scheme 51: Syntheses of (+)-deoxocassine ((2S,3S,6R)-190a, R = C12H25) and (+)-spectaline ((2S,3S,6R)-190b, R ...
Scheme 52: Synthesis of (−)-microgrewiapine A ((2S,3R,6S)-194a) and (+)-microcosamine A ((2S,3R,6S)-194b). Rea...
Scheme 53: Syntheses of ʟ-1-deoxynojirimycin ((2S,3S,4S,5R)-200), ʟ-1-deoxymannojirimycin ((2S,3S,4S,5S)-200) ...
Scheme 54: Syntheses of 1-deoxy-ᴅ-galacto-homonojirimycin (2R,3S,4R,5S)-211. Reagents and conditions: a) MeONH...
Scheme 55: Syntheses of 7a-epi-hyacinthacine A1 (1S,2R,3R,7aS)-220. Reagents and conditions: a) TfOTBDMS, 2,6-...
Scheme 56: Syntheses of 8-deoxyhyacinthacine A1 ((1S,2R,3R,7aR)-221). Reagents and conditions: a) H2, Pd/C, PT...
Scheme 57: Syntheses of (+)-lentiginosine ((1S,2S,8aS)-227). Reagents and conditions: a) (EtO)2P(O)CH2COOEt, L...
Scheme 58: Syntheses of 8-epi-swainsonine (1S,2R,8S,8aR)-231. Reagents and conditions: a) Ph3P=CHCOOMe, MeOH, ...
Scheme 59: Synthesis of a protected vinylpiperidine (2S,3R)-237, a key intermediate in the synthesis of (−)-sw...
Scheme 60: Synthesis of a modified carbapenem 245. Reagents and conditions: a) AcOEt, LiHMDS, THF, −78 °C, 1.5...
Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage
- Gagandeep Kour Reen,
- Ashok Kumar and
- Pratibha Sharma
Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165
Graphical Abstract
Figure 1: Various drugs having IP nucleus.
Figure 2: Participation percentage of various TMs for the syntheses of IPs.
Scheme 1: CuI–NaHSO4·SiO2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 2: Experimental examination of reaction conditions.
Scheme 3: One-pot tandem reaction for the synthesis of 2-haloimidazopyridines.
Scheme 4: Mechanistic scheme for the synthesis of 2-haloimidazopyridine.
Scheme 5: Copper-MOF-catalyzed three-component reaction (3-CR) for imidazo[1,2-a]pyridines.
Scheme 6: Mechanism for copper-MOF-driven synthesis.
Scheme 7: Heterogeneous synthesis via titania-supported CuCl2.
Scheme 8: Mechanism involving oxidative C–H functionalization.
Scheme 9: Heterogeneous synthesis of IPs.
Scheme 10: One-pot regiospecific synthesis of imidazo[1,2-a]pyridines.
Scheme 11: Vinyl azide as an unprecedented substrate for imidazo[1,2-a]pyridines.
Scheme 12: Radical pathway.
Scheme 13: Cu(I)-catalyzed transannulation approach for imidazo[1,5-a]pyridines.
Scheme 14: Plausible radical pathway for the synthesis of imidazo[1,5-a]pyridines.
Scheme 15: A solvent-free domino reaction for imidazo[1,2-a]pyridines.
Scheme 16: Cu-NPs-mediated synthesis of imidazo[1,2-a]pyridines.
Scheme 17: CuI-catalyzed synthesis of isoxazolylimidazo[1,2-a]pyridines.
Scheme 18: Functionalization of 4-bromo derivative via Sonogashira coupling reaction.
Scheme 19: A plausible reaction pathway.
Scheme 20: Cu(I)-catalyzed intramolecular oxidative C–H amidation reaction.
Scheme 21: One-pot synthetic reaction for imidazo[1,2-a]pyridine.
Scheme 22: Plausible reaction mechanism.
Scheme 23: Cu(OAc)2-promoted synthesis of imidazo[1,2-a]pyridines.
Scheme 24: Mechanism for aminomethylation/cycloisomerization of propiolates with imines.
Scheme 25: Three-component synthesis of imidazo[1,2-a]pyridines.
Figure 3: Scope of pyridin-2(1H)-ones and acetophenones.
Scheme 26: CuO NPS-promoted A3 coupling reaction.
Scheme 27: Cu(II)-catalyzed C–N bond formation reaction.
Scheme 28: Mechanism involving Chan–Lam/Ullmann coupling.
Scheme 29: Synthesis of formyl-substituted imidazo[1,2-a]pyridines.
Scheme 30: A tandem sp3 C–H amination reaction.
Scheme 31: Probable mechanistic approach.
Scheme 32: Dual catalytic system for imidazo[1,2-a]pyridines.
Scheme 33: Tentative mechanism.
Scheme 34: CuO/CuAl2O4/ᴅ-glucose-promoted 3-CCR.
Scheme 35: A tandem CuOx/OMS-2-based synthetic strategy.
Figure 4: Biomimetic catalytic oxidation in the presence of electron-transfer mediators (ETMs).
Scheme 36: Control experiment.
Scheme 37: Copper-catalyzed C(sp3)–H aminatin reaction.
Scheme 38: Reaction of secondary amines.
Scheme 39: Probable mechanistic pathway.
Scheme 40: Coupling reaction of α-azidoketones.
Scheme 41: Probable pathway.
Scheme 42: Probable mechanism with free energy calculations.
Scheme 43: MCR for cyanated IP synthesis.
Scheme 44: Substrate scope for the reaction.
Scheme 45: Reaction mechanism.
Scheme 46: Probable mechanistic pathway for Cu/ZnAl2O4-catalyzed reaction.
Scheme 47: Copper-catalyzed double oxidative C–H amination reaction.
Scheme 48: Application towards different coupling reactions.
Scheme 49: Reaction mechanism.
Scheme 50: Condensation–cyclization approach for the synthesis of 1,3-diarylated imidazo[1,5-a]pyridines.
Scheme 51: Optimized reaction conditions.
Scheme 52: One-pot 2-CR.
Scheme 53: One-pot 3-CR without the isolation of chalcone.
Scheme 54: Copper–Pybox-catalyzed cyclization reaction.
Scheme 55: Mechanistic pathway catalyzed by Cu–Pybox complex.
Scheme 56: Cu(II)-promoted C(sp3)-H amination reaction.
Scheme 57: Wider substrate applicability for the reaction.
Scheme 58: Plausible reaction mechanism.
Scheme 59: CuI assisted C–N cross-coupling reaction.
Scheme 60: Probable reaction mechanism involving sp3 C–H amination.
Scheme 61: One-pot MCR-catalyzed by CoFe2O4/CNT-Cu.
Scheme 62: Mechanistic pathway.
Scheme 63: Synthetic scheme for 3-nitroimidazo[1,2-a]pyridines.
Scheme 64: Plausible mechanism for CuBr-catalyzed reaction.
Scheme 65: Regioselective synthesis of halo-substituted imidazo[1,2-a]pyridines.
Scheme 66: Synthesis of 2-phenylimidazo[1,2-a]pyridines.
Scheme 67: Synthesis of diarylated compounds.
Scheme 68: CuBr2-mediated one-pot two-component oxidative coupling reaction.
Scheme 69: Decarboxylative cyclization route to synthesize 1,3-diarylimidazo[1,5-a]pyridines.
Scheme 70: Mechanistic pathway.
Scheme 71: C–H functionalization reaction of enamines to produce diversified heterocycles.
Scheme 72: A plausible mechanism.
Scheme 73: CuI-promoted aerobic oxidative cyclization reaction of ketoxime acetates and pyridines.
Scheme 74: CuI-catalyzed pathway for the formation of imidazo[1,2-a]pyridine.
Scheme 75: Mechanistic pathway.
Scheme 76: Mechanistic rationale for the synthesis of products.
Scheme 77: Copper-catalyzed synthesis of vinyloxy-IP.
Scheme 78: Regioselective product formation with propiolates.
Scheme 79: Proposed mechanism for vinyloxy-IP formation.
Scheme 80: Regioselective synthesis of 3-hetero-substituted imidazo[1,2-a]pyridines with different reaction su...
Scheme 81: Mechanistic pathway.
Scheme 82: CuI-mediated synthesis of 3-formylimidazo[1,2-a]pyridines.
Scheme 83: Radical pathway for 3-formylated IP synthesis.
Scheme 84: Pd-catalyzed urea-cyclization reaction for IPs.
Scheme 85: Pd-catalyzed one-pot-tandem amination and intramolecular amidation reaction.
Figure 5: Scope of aniline nucleophiles.
Scheme 86: Pd–Cu-catalyzed Sonogashira coupling reaction.
Scheme 87: One-pot amide coupling reaction for the synthesis of imidazo[4,5-b]pyridines.
Scheme 88: Urea cyclization reaction for the synthesis of two series of pyridines.
Scheme 89: Amidation reaction for the synthesis of imidazo[4,5-b]pyridines.
Figure 6: Amide scope.
Scheme 90: Pd NPs-catalyzed 3-component reaction for the synthesis of 2,3-diarylated IPs.
Scheme 91: Plausible mechanistic pathway for Pd NPs-catalyzed MCR.
Scheme 92: Synthesis of chromenoannulated imidazo[1,2-a]pyridines.
Scheme 93: Mechanism for the synthesis of chromeno-annulated IPs.
Scheme 94: Zinc oxide NRs-catalyzed synthesis of imidazo[1,2-a]azines/diazines.
Scheme 95: Zinc oxide-catalyzed isocyanide based GBB reaction.
Scheme 96: Reaction pathway for ZnO-catalyzed GBB reaction.
Scheme 97: Mechanistic pathway.
Scheme 98: ZnO NRs-catalyzed MCR for the synthesis of imidazo[1,2-a]azines.
Scheme 99: Ugi type GBB three-component reaction.
Scheme 100: Magnetic NPs-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 101: Regioselective synthesis of 2-alkoxyimidazo[1,2-a]pyridines catalyzed by Fe-SBA-15.
Scheme 102: Plausible mechanistic pathway for the synthesis of 2-alkoxyimidazopyridine.
Scheme 103: Iron-catalyzed synthetic approach.
Scheme 104: Iron-catalyzed aminooxygenation reaction.
Scheme 105: Mechanistic pathway.
Scheme 106: Rh(III)-catalyzed double C–H activation of 2-substituted imidazoles and alkynes.
Scheme 107: Plausible reaction mechanism.
Scheme 108: Rh(III)-catalyzed non-aromatic C(sp2)–H bond activation–functionalization for the synthesis of imid...
Scheme 109: Reactivity and selectivity of different substrates.
Scheme 110: Rh-catalyzed direct C–H alkynylation by Li et al.
Scheme 111: Suggested radical mechanism.
Scheme 112: Scandium(III)triflate-catalyzed one-pot reaction and its mechanism for the synthesis of benzimidazo...
Scheme 113: RuCl3-assisted Ugi-type Groebke–Blackburn condensation reaction.
Scheme 114: C-3 aroylation via Ru-catalyzed two-component reaction.
Scheme 115: Regioselective synthetic mechanism.
Scheme 116: La(III)-catalyzed one-pot GBB reaction.
Scheme 117: Mechanistic approach for the synthesis of imidazo[1,2-a]pyridines.
Scheme 118: Synthesis of imidazo[1,2-a]pyridine using LaMnO3 NPs under neat conditions.
Scheme 119: Mechanistic approach.
Scheme 120: One-pot 3-CR for regioselective synthesis of 2-alkoxy-3-arylimidazo[1,2-a]pyridines.
Scheme 121: Formation of two possible products under optimization of the catalysts.
Scheme 122: Mechanistic strategy for NiFe2O4-catalyzed reaction.
Scheme 123: Two-component reaction for synthesizing imidazodipyridiniums.
Scheme 124: Mechanistic scheme for the synthesis of imidazodipyridiniums.
Scheme 125: CuI-catalyzed arylation of imidazo[1,2-a]pyridines.
Scheme 126: Mechanism for arylation reaction.
Scheme 127: Cupric acetate-catalyzed double carbonylation approach.
Scheme 128: Radical mechanism for double carbonylation of IP.
Scheme 129: C–S bond formation reaction catalyzed by cupric acetate.
Scheme 130: Cupric acetate-catalyzed C-3 formylation approach.
Scheme 131: Control experiments for signifying the role of DMSO and oxygen.
Scheme 132: Mechanism pathway.
Scheme 133: Copper bromide-catalyzed CDC reaction.
Scheme 134: Extension of the substrate scope.
Scheme 135: Plausible radical pathway.
Scheme 136: Transannulation reaction for the synthesis of imidazo[1,5-a]pyridines.
Scheme 137: Plausible reaction pathway for denitrogenative transannulation.
Scheme 138: Cupric acetate-catalyzed C-3 carbonylation reaction.
Scheme 139: Plausible mechanism for regioselective C-3 carbonylation.
Scheme 140: Alkynylation reaction at C-2 of 3H-imidazo[4,5-b]pyridines.
Scheme 141: Two-way mechanism for C-2 alkynylation of 3H-imidazo[4,5-b]pyridines.
Scheme 142: Palladium-catalyzed SCCR approach.
Scheme 143: Palladium-catalyzed Suzuki coupling reaction.
Scheme 144: Reaction mechanism.
Scheme 145: A phosphine free palladium-catalyzed synthesis of C-3 arylated imidazopyridines.
Scheme 146: Palladium-mediated Buchwald–Hartwig cross-coupling reaction.
Figure 7: Structure of the ligands optimized.
Scheme 147: Palladium acetate-catalyzed direct arylation of imidazo[1,2-a]pyridines.
Scheme 148: Palladium acetate-catalyzed mechanistic pathway.
Scheme 149: Palladium acetate-catalyzed regioselective arylation reported by Liu and Zhan.
Scheme 150: Mechanism for selective C-3 arylation of IP.
Scheme 151: Pd(II)-catalyzed alkenylation reaction with styrenes.
Scheme 152: Pd(II)-catalyzed alkenylation reaction with acrylates.
Scheme 153: A two way mechanism.
Scheme 154: Double C–H activation reaction catalyzed by Pd(OAc)2.
Scheme 155: Probable mechanism.
Scheme 156: Palladium-catalyzed decarboxylative coupling.
Scheme 157: Mechanistic cycle for decarboxylative arylation reaction.
Scheme 158: Ligand-free approach for arylation of imidazo[1,2-a]pyridine-3-carboxylic acids.
Scheme 159: Mechanism for ligandless arylation reaction.
Scheme 160: NHC-Pd(II) complex assisted arylation reaction.
Scheme 161: C-3 arylation of imidazo[1,2-a]pyridines with aryl bromides catalyzed by Pd(OAc)2.
Scheme 162: Pd(II)-catalyzed C-3 arylations with aryl tosylates and mesylates.
Scheme 163: CDC reaction for the synthesis of imidazo[1,2-a]pyridines.
Scheme 164: Plausible reaction mechanism for Pd(OAc)2-catalyzed synthesis of imidazo[1,2-a]pyridines.
Scheme 165: Pd-catalyzed C–H amination reaction.
Scheme 166: Mechanism for C–H amination reaction.
Scheme 167: One-pot synthesis for 3,6-di- or 2,3,6-tri(hetero)arylimidazo[1,2-a]pyridines.
Scheme 168: C–H/C–H cross-coupling reaction of IPs and azoles catalyzed by Pd(II).
Scheme 169: Mechanistic cycle.
Scheme 170: Rh-catalyzed C–H arylation reaction.
Scheme 171: Mechanistic pathway for C–H arylation of imidazo[1,2-a]pyridine.
Scheme 172: Rh(III)-catalyzed double C–H activation of 2-phenylimidazo[1,2-a]pyridines and alkynes.
Scheme 173: Rh(III)-catalyzed mechanistic pathway.
Scheme 174: Rh(III)-mediated oxidative coupling reaction.
Scheme 175: Reactions showing functionalization of the product obtained by the group of Kotla.
Scheme 176: Mechanism for Rh(III)-catalyzed oxidative coupling reaction.
Scheme 177: Rh(III)-catalyzed C–H activation reaction.
Scheme 178: Mechanistic cycle.
Scheme 179: Annulation reactions of 2-arylimidazo[1,2-a]pyridines and alkynes.
Scheme 180: Two-way reaction mechanism for annulations reaction.
Scheme 181: [RuCl2(p-cymene)]2-catalyzed C–C bond formation reaction.
Scheme 182: Reported reaction mechanism.
Scheme 183: Fe(III) catalyzed C-3 formylation approach.
Scheme 184: SET mechanism-catalyzed by Fe(III).
Scheme 185: Ni(dpp)Cl2-catalyzed KTC coupling.
Scheme 186: Pd-catalyzed SM coupling.
Scheme 187: Vanadium-catalyzed coupling of IP and NMO.
Scheme 188: Mechanistic cycle.
Scheme 189: Selective C3/C5–H bond functionalizations by mono and bimetallic systems.
Scheme 190: rGO-Ni@Pd-catalyzed C–H bond arylation of imidazo[1,2-a]pyridine.
Scheme 191: Mechanistic pathway for heterogeneously catalyzed arylation reaction.
Scheme 192: Zinc triflate-catalyzed coupling reaction of substituted propargyl alcohols.
Synthesis of nonracemic hydroxyglutamic acids
- Dorota G. Piotrowska,
- Iwona E. Głowacka,
- Andrzej E. Wróblewski and
- Liwia Lubowiecka
Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22
- obtained after cleavage of 84 under basic conditions. From pyroglutamic acid In case of low availability of selected stereoisomers of 4-hydroxyprolines asymmetric syntheses of enantiomeric 4-hydroxypyroglutamates have been elaborated employing 1,3-dipolar cycloadditions of homochiral nitrones and acrylates
Graphical Abstract
Figure 1: Structure of L-glutamic acid.
Figure 2: 3-Hydroxy- (2), 4-hydroxy- (3) and 3,4-dihydroxyglutamic acids (4).
Figure 3: Enantiomers of 3-hydroxyglutamic acid (2).
Scheme 1: Synthesis of (2S,3R)-2 from (R)-Garner's aldehyde. Reagents and conditions: a) MeOCH=CH–CH(OTMS)=CH2...
Scheme 2: Synthesis of (2S,3R)-2 and (2S,3S)-2 from (R)-Garner’s aldehyde. Reagents and conditions: a) H2C=CH...
Scheme 3: Two-carbon homologation of the protected L-serine. Reagents and conditions: a) Fmoc-succinimide, Na2...
Scheme 4: Synthesis of di-tert-butyl ester of (2R,3S)-2 from L-serine. Reagents and conditions: a) PhSO2Cl, K2...
Scheme 5: Synthesis of (2R,3S)-2 from O-benzyl-L-serine. Reagents and conditions: a) (CF3CH2O)2P(O)CH2COOMe, ...
Scheme 6: Synthesis of (2S,3R)-2 employing a one-pot cis-olefination–conjugate addition sequence. Reagents an...
Scheme 7: Synthesis of the orthogonally protected (2S,3R)-2 from a chiral aziridine. Reagents and conditions:...
Scheme 8: Synthesis of N-Boc-protected (2S,3R)-2 from D-phenylglycine. Reagents and conditions: a) BnMgCl, et...
Scheme 9: Synthesis of (2S,3R)-2 employing ketopinic acid as chiral auxiliary. Reagents and conditions: a) Br2...
Scheme 10: Synthesis of dimethyl ester of (2S,3R)-2 employing (1S)-2-exo-methoxyethoxyapocamphane-1-carboxylic...
Scheme 11: Synthesis of N-Boc-protected dimethyl ester of (2S,3R)-2 from (S)-N-(1-phenylethyl)thioacetamide. R...
Scheme 12: Synthesis of N-Boc-protected dimethyl ester of (2S,3R)-2 via Sharpless epoxidation. Reagents and co...
Scheme 13: Synthesis of (2S,3S)-2 from the imide 51. Reagents and conditions: a) NaBH4, MeOH/CH2Cl2; b) Ac2O, ...
Scheme 14: Synthesis of (2R,3S)-2 and (2S,3S)-2 from the acetolactam 55 (PMB = p-methoxybenzyl). Reagents and ...
Scheme 15: Synthesis of (2S,3R)-2 from D-glucose. Reagents and conditions: a) NaClO2, 30% H2O2, NaH2PO4, MeCN;...
Figure 4: Enantiomers of 3-hydroxyglutamic acid (3).
Scheme 16: Synthesis of (4S)-4-hydroxy-L-glutamic acid [(2S,4S)-3] by electrophilic hydroxylation. Reagents an...
Scheme 17: Synthesis of all stereoisomers of 4-hydroxyglutamic acid (3). Reagents and conditions: a) Br2, PBr5...
Scheme 18: Synthesis of the orthogonally protected 4-hydroxyglutamic acid (2S,4S)-73. Reagents and conditions:...
Scheme 19: Synthesis of (2S,4R)-4-acetyloxyglutamic acid as a component of a dipeptide. Reagents and condition...
Scheme 20: Synthesis of N-Boc-protected dimethyl esters of (2S,4R)- and (2S,4S)-3 from (2S,4R)-4-hydroxyprolin...
Scheme 21: Synthesis of orthogonally protected (2S,4S)-3 from (2S,4R)-4-hydroxyproline. Reagents and condition...
Scheme 22: Synthesis of the protected (4R)-4-hydroxy-L-pyroglutamic acid (2S,4R)-87 by electrophilic hydroxyla...
Figure 5: Enantiomers of 3,4-dihydroxy-L-glutamic acid (4).
Scheme 23: Synthesis of (2S,3S,4R)-4 from the epoxypyrrolidinone 88. Reagents and conditions: a) MeOH, THF, KC...
Scheme 24: Synthesis of (2S,3R,4R)-4 from the orthoester 92. Reagents and conditions: a) OsO4, NMO, acetone/wa...
Scheme 25: Synthesis of (2S,3S,4S)-4 from the aziridinolactone 95. Reagents and conditions: a) BnOH, BF3·OEt2,...
Scheme 26: Synthesis of (2S,3S,4R)-4 and (2R,3S,4R)-4 from cyclic imides 106. Reagents and conditions: a) NaBH4...
Scheme 27: Synthesis of (2R,3R,4R)-4 and (2S,3R,4R)-4 from the cyclic meso-imide 110. Reagents and conditions:...
Scheme 28: Synthesis of (2S,3S,4S)-4 from the protected serinal (R)-23. Reagents and conditions: a) Ph3P=CHCOO...
Scheme 29: Synthesis of (2S,3S,4S)-4 from O-benzyl-N-Boc-D-serine. Reagents and conditions: a) ClCOOiBu, TEA, ...
Scheme 30: Synthesis of (2S,3S,4R)-127 by enantioselective conjugate addition and asymmetric dihydroxylation. ...
Figure 6: Structures of selected compounds containing hydroxyglutamic motives (in blue).
Cross metathesis-mediated synthesis of hydroxamic acid derivatives
- Shital Kumar Chattopadhyay,
- Subhankar Ghosh and
- Suman Sil
Beilstein J. Org. Chem. 2018, 14, 3070–3075, doi:10.3762/bjoc.14.285
- CM-mediated synthesis of functionalized alkenes of various kinds continue to appear. For example, cross metathesis with acrylates [8][9][10], α,ß-unsaturated acid chlorides [11], acrylamides [12][13][14], vinyl sulfones [15], vinylphosphine oxides [16], vinyl phosphonates [17], enones [18], and
Graphical Abstract
Figure 1: Some bioactive molecules containing hydroxamate functionality.
Scheme 1: Cross metathesis between a class-I alkene and N-benzyloxyacryl amide.
Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region
- Aude-Héloise Bonardi,
- Frédéric Dumur,
- Guillaume Noirbent,
- Jacques Lalevée and
- Didier Gigmes
Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282
- produced to initiate the polymerization. By formation of radicals, the polymerization of C=C functions such as (meth)acrylates or styrene can be initiated. With cations or acids as initiating species, epoxy monomers can be polymerized. Both types of polymerization are widely used both in academic and
- , formations of interpenetrated polymer networks (IPN) are also mentioned. For the three systems proposed above, formation of aryl radicals is observed. These radicals are able to initiate the free radical polymerization of (meth)acrylates [1]. In the photocatalytic cycle (Figure 5C), EDB(−H)• radicals are
- infrared spectroscopy, following the epoxy function. Other monomers presented in Scheme 6 are acrylates and methacrylates and can be polymerized by free radical polymerization. Photopolymerization of these compounds can also be characterized by FTIR measurement, following the C=C double bound conversion
Graphical Abstract
Figure 1: Typical oxidative and reductive cycle for a photoredox catalyst (PC).
Figure 2: Transitions involved in absorbing species containing π, σ and n electrons.
Figure 3: Ligand to metal charge transfer (illustrated here for a d6 metal complex).
Figure 4: Metal to ligand charge transfer (illustrated here for a d5 metal complex).
Scheme 1: Structures of additives involved in the photoredox catalytic cycles.
Figure 5: Catalytic cycles involved with iodonium salt and (A) (TMS)3SiH, (B) NVK and (C) EDB.
Scheme 2: Structures of photoredox metal-based catalysts.
Scheme 3: Photocatalytical cycle for the Ru complex.
Scheme 4: Structures of photoredox organocatalysts.
Scheme 5: Diversity of the chemical structures of photoredox organocatalysts.
Scheme 6: Structures of benchmarked monomers.
Scheme 7: Structure of the CARET additive.
Scheme 8: Photoredox catalysis mechanism of a visible light-mediated living radical polymerization. (Abbrevia...
Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins
- Christiane Schultze and
- Bernd Schmidt
Beilstein J. Org. Chem. 2018, 14, 2991–2998, doi:10.3762/bjoc.14.278
- , we investigated the synthesis of coumarins with annellated unsaturated lactones starting from the same 8-allylcoumarins 8 (Scheme 1). For the synthesis of oxepin-2-one-annellated coumarins 13 compounds 8 were first converted to the corresponding acrylates 12 with acryloyl chloride (Table 3). RCM of
- these acrylates turned out to be not straightforward but required some optimization (Table 4). In particular, a reduced initial substrate concentration of 0.01 M and reaction temperatures of 110 °C (Table 4, entry 6) led to a smooth conversion to the desired oxepin-2-ones 13, whereas ambient or slightly
- completely in this case (Table 4, entries 3 and 4). The beneficial effect of low initial substrate concentrations on RCM reactions with acrylates has previously been described [65] and was later systematically investigated by one of us [66]. A possible access to the pyran-2-one-annellated coumarin
Graphical Abstract
Figure 1: Illustration of coumarin taxonomy.
Scheme 1: Synthesis of oxepin-2-one-annellated coumarins 13 by RCM of acrylates 12.
Scheme 2: Attempted synthesis of pyran-2-one-annellated coumarin 15d via isomerization-RCM.
Scheme 3: Synthesis of aza-annellated coumarin 21 and attempted synthesis of indole 22.
Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
- Glwadys Gagnot,
- Vincent Hervin,
- Eloi P. Coutant,
- Sarah Desmons,
- Racha Baatallah,
- Victor Monnot and
- Yves L. Janin
Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263
- acetic anhydride afforded a mixture of compounds containing variable amounts of the expected acrylates 2a–s. No attempts were made to purify these as they were immediately subjected to a reduction of its double bond using sodium borohydride [9][10] in refluxing isopropanol in order to properly isolate
- . Indeed, the best overall yields are observed when starting from the electronically similar 2-methoxy acetal 5b or the 4-methoxy analog 5d, as well as the 4-benzyloxy acetal 5e. (ii) Secondly, the reduction of acrylates 2a–s to compounds 6a–s was achieved with sodium borohydride and the resulting basic
- conditions could be detrimental to the stability of some of these α-nitro acrylates. In the past, such reductions have been achieved under fairly uncommon conditions (NaBH4 in a mixture of isopropanol and chloroform over a large proportion of silica gel) [11][12]. However, when tried, no real overall
Graphical Abstract
Scheme 1: α-Amino esters from ethyl nitroacetate (4).
Scheme 2: Preparations of α-amino esters 10, 12 and 14.
Scheme 3: Syntheses of α-amino ester 18 and piperazinediones 23a,b.
Scheme 4: Syntheses of α-hydroximino ester 29 and α-amino ester 36.
Scheme 5: Synthesis of α-amino ester 43.
DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives
- Soumitra Guin,
- Raman Gupta,
- Debashis Majee and
- Sampak Samanta
Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254
- generality and scope of the reaction by reacting several aryl/heteroaryl-substituted MBH carbonates derived from acrylates 2a–j and 4-methyl-N-sulfonyl ketimines 1a–e under present sequential reaction conditions. The results are incorporated in Scheme 3. The regioselective allylic alkylation/aromatization
Graphical Abstract
Figure 1: Drugs and agrochemicals having a nicotinic acid derivative.
Scheme 1: One-pot access to (2-hydroxyaryl)pyridines.
Scheme 2: A possible mechanism for this sequential reaction.
Scheme 3: Substrate scope for (2-hydroxyaryl)nicotinates syntheses. The reaction was performed with 1a–e (0.2...
Scheme 4: One-pot synthesis of (2-hydroxyaryl)nicotinonitriles 5ak–5am.
Learning from B12 enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis
- Keishiro Tahara,
- Ling Pan,
- Toshikazu Ono and
- Yoshio Hisaeda
Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232
- (III) form of 1 has recently been found to catalyze atom transfer radical addition of alkyl halides to olefins (phenyl vinyl sulfone and acrylates) in the presence of NaBH4 [115]. In addition, a new light-driven method for generating acyl radicals from 2-S-pyridyl thioesters was developed through the
Graphical Abstract
Figure 1: (a) Structure and (b) reactivity of B12.
Figure 2: (a) Schematic representation of B12 enzyme-involving systems. (b) Construction of biomimetic and bi...
Scheme 1: (a) Carbon-skeleton rearrangement mediated by a coenzyme B12-depenedent enzyme. (b) Electrochemical...
Scheme 2: Electrochemical carbon-skeleton arrangements mediated by B12 model complexes.
Figure 3: Key electrochemical reactivity of 1 and 2 in methylated forms.
Scheme 3: Carbon-skeleton arrangements mediated by B12-vesicle artificial enzymes.
Scheme 4: Carbon-skeleton arrangements mediated by B12-HSA artificial enzymes.
Scheme 5: Photochemical carbon-skeleton arrangements mediated by B12-Ru@MOF.
Scheme 6: (a) Methyl transfer reaction mediated by B12-dependent methionine synthase. (b) Methyl transfer rea...
Scheme 7: Methyl transfer reaction for the detoxification of inorganic arsenics.
Scheme 8: (a) Dechlorination of 1,1,2,2-tetrarchloroethene mediated by a reductive dehalogenase. (b) Electroc...
Scheme 9: Visible-light-driven dechlorination of DDT using 1 in the presence of photosensitizers.
Scheme 10: 1,2-Migration of a phenyl group mediated by the visible-light-driven catalytic system composed of 1...
Scheme 11: Ring-expansion reactions mediated by the B12-TiO2 hybrid catalyst with UV-light irradiation.
Scheme 12: Trifluoromethylation and perfluoroalkylation of aromatic compounds achieved through electrolysis wi...
Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source
- Tetsuaki Fujihara and
- Yasushi Tsuji
Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221
- reductant, carboxyzincation and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc occur efficiently. Rh complexes also catalyze the carboxylation of arylboronic esters, C(sp2)–H carboxylation of aromatic compounds, and hydrocarboxylation of styrene derivatives. The Rh-catalyzed
- carboxylation of allylarenes when a suitable ligand is used. In the presence of zinc powder, the Co-catalyzed carboxyzincation of alkynes and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc proceed in an efficient manner. Visible-light-driven hydrocarboxylation reactions are shown
- , thereby giving the carboxyzincated product and regenerating Co(I) species A (step c). We also achieved the four-component coupling of alkynes 16, acrylates 18, CO2, and Zn metal, as depicted in Scheme 18 [40]. As a model reaction, the reaction using diphenylacetylene (16h), butyl acrylate (18a), CO2, and
Graphical Abstract
Scheme 1: Optimization of the Co-catalyzed carboxylation of 1a.
Scheme 2: Co-catalyzed carboxylation of propargyl acetates 1.
Scheme 3: Plausible reaction mechanism for the Co-catalyzed carboxylation of propargyl acetates 1.
Scheme 4: Optimization of the Co-catalyzed carboxylation of 3a.
Scheme 5: Co-catalyzed carboxylation of vinyl triflates 3.
Scheme 6: Co-catalyzed carboxylation of a sterically hindered aryl triflate 5.
Scheme 7: Optimization of the Co-catalyzed carboxylation of 7a.
Scheme 8: Scope of the reductive carboxylation of α,β-unsaturated nitriles 7.
Scheme 9: Scope of the carboxylation of α,β-unsaturated carboxamides 9.
Scheme 10: Optimization of the Co-catalyzed carboxylation of 11a.
Scheme 11: Scope of the carboxylation of allylarenes 11.
Scheme 12: Scope of the carboxylation of 1,4-diene derivatives 14.
Scheme 13: Plausible reaction mechanism for the Co-catalyzed C(sp3)–H carboxylation of allylarenes.
Scheme 14: Optimization of the Co-catalyzed carboxyzincation of 16a.
Scheme 15: Derivatization of the carboxyzincated product.
Scheme 16: Co-catalyzed carboxyzincation of alkynes 16.
Scheme 17: Plausible reaction mechanism for the Co-catalyzed carboxyzincation of alkynes 16.
Scheme 18: Co-catalyzed four-component coupling of alkynes 16, acrylates 18, CO2, and zinc.
Scheme 19: Proposed reaction mechanism for the Co-catalyzed four-component coupling.
Scheme 20: Visible-light-driven hydrocarboxylation of alkynes.
Scheme 21: Visible-light-driven synthesis of γ-hydroxybutenolides from ortho-ester-substituted aryl alkynes.
Scheme 22: One-pot synthesis of coumarines and 2-quinolones via hydrocarboxylation/alkyne isomerization/cycliz...
Scheme 23: Proposed reaction mechanism for the Co-catalyzed carboxylative cyclization of ortho-substituted aro...
Scheme 24: Rh-catalyzed carboxylation of arylboronic esters 25.
Scheme 25: Rh-catalyzed carboxylation of alkenylboronic esters 27.
Scheme 26: Plausible reaction mechanism for the Rh-catalyzed carboxylation of arylboronic esters 25.
Scheme 27: Ligand effect on the Rh-catalyzed carboxylation of 2-phenylpyridine 29a.
Scheme 28: Rh-catalyzed chelation-assisted C(sp2)–H bond carboxylation with CO2.
Scheme 29: Reaction mechanism for the Rh-catalyzed C(sp2)–H carboxylation of 2-pyridylarenes 29.
Scheme 30: Carboxylation of C(sp2)–H bond with CO2.
Scheme 31: Carboxylation of C(sp2)–H bond with CO2.
Scheme 32: Reaction mechanism for the Rh-catalyzed C(sp2)–H carboxylation of 2-arylphenols 34.
Scheme 33: Hydrocarboxylation of styrene derivatives with CO2.
Scheme 34: Hydrocarboxylation of α,β-unsaturated esters with CO2.
Scheme 35: Asymmetric hydrocarboxylation of α,β-unsaturated esters with CO2.
Scheme 36: Proposed reaction mechanism for the Rh-catalyzed hydrocarboxylation of C–C double bonds with CO2.
Scheme 37: Visible-light-driven hydrocarboxylation with CO2.
Scheme 38: Visible-light-driven Rh-catalyzed hydrocarboxylation of C–C double bonds with CO2.
Scheme 39: Optimization of reaction conditions on the Rh-catalyzed [2 + 2 + 2] cycloaddition of diyne 42a and ...
Scheme 40: [2 + 2 + 2] Cycloaddition of diyne and CO2.
Scheme 41: Proposed reaction pathways for the Rh-catalyzed [2 + 2 + 2] cycloaddition of diyne and CO2.
Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis
- Gwendal Grelier,
- Benjamin Darses and
- Philippe Dauban
Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128
- –I motif (Scheme 22) [62]. Hence aryl- and alkyl-substituted terminal alkynes can be coupled via a Sonogashira reaction when PPh3 is used as ligand, while the use of diphenylphosphinoferrocenyl ligand (dppf) allows the Heck-type coupling of acrylates, vinyl ketones and electron-poor styrene
Graphical Abstract
Scheme 1: Strategies to address the issue of sustainability with polyvalent organoiodine reagents.
Scheme 2: Functionalization of ketones and alkenes with IBX.
Scheme 3: Functionalization of pyrroles with DMP.
Scheme 4: Catalytic benzoyloxy-trifluoromethylation reported by Szabó.
Scheme 5: Catalytic benzoyloxy-trifluoromethylation reported by Mideoka.
Scheme 6: Catalytic 1,4-benzoyloxy-trifluoromethylation of dienes.
Scheme 7: Catalytic benzoyloxy-trifluoromethylation of allylamines.
Scheme 8: Catalytic benzoyloxy-trifluoromethylation of enynes.
Scheme 9: Catalytic benzoyloxy-trifluoromethylation of allenes.
Scheme 10: Alkynylation of N-(aryl)imines with EBX for the formation of furans.
Scheme 11: Catalytic benzoyloxy-alkynylation of diazo compounds.
Scheme 12: Catalytic asymmetric benzoyloxy-alkynylation of diazo compounds.
Scheme 13: Catalytic 1,2-benzoyloxy-azidation of alkenes.
Scheme 14: Catalytic 1,2-benzoyloxy-azidation of enamides.
Scheme 15: Catalytic 1,2-benzoyloxy-iodination of alkenes.
Scheme 16: Seminal study with cyclic diaryl-λ3-iodane.
Scheme 17: Synthesis of alkylidenefluorenes from cyclic diaryl-λ3-iodanes.
Scheme 18: Synthesis of alkyne-substituted alkylidenefluorenes.
Scheme 19: Synthesis of phenanthrenes from cyclic diaryl-λ3-iodanes.
Scheme 20: Synthesis of dibenzocarbazoles from cyclic diaryl-λ3-iodanes.
Scheme 21: Synthesis of triazolophenantridines from cyclic diaryl-λ3-iodanes.
Scheme 22: Synthesis of functionalized benzoxazoles from cyclic diaryl-λ3-iodanes.
Scheme 23: Sequential difunctionalization of cyclic diaryl-λ3-iodanes.
Scheme 24: Double Suzuki–Miyaura coupling reaction of cyclic diaryl-λ3-iodanes.
Scheme 25: Synthesis of a δ-carboline from cyclic diaryl-λ3-iodane.
Scheme 26: Synthesis of N-(aryl)carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 27: Synthesis of carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 28: Synthesis of carbazoles and acridines from cyclic diaryl-λ3-iodanes.
Scheme 29: Synthesis of dibenzothiophenes from cyclic diaryl-λ3-iodanes.
Scheme 30: Synthesis of various sulfur heterocycles from cyclic diaryl-λ3-iodanes.
Scheme 31: Synthesis of dibenzothioheterocycles from cyclic diaryl-λ3-iodanes.
Scheme 32: Synthesis of dibenzosulfides and dibenzoselenides from cyclic diaryl-λ3-iodanes.
Scheme 33: Synthesis of dibenzosulfones from cyclic diaryl-λ3-iodanes.
Scheme 34: Seminal study with linear diaryl-λ3-iodanes.
Scheme 35: N-Arylation of benzotriazole with symmetrical diaryl-λ3-iodanes.
Scheme 36: Tandem catalytic C–H/N–H arylation of indoles with diaryl-λ3-iodanes.
Scheme 37: Tandem N-arylation/C(sp2)–H arylation with diaryl-λ3-iodanes.
Scheme 38: Catalytic intermolecular diarylation of anilines with diaryl-λ3-iodanes.
Scheme 39: Catalytic synthesis of diarylsulfides with diaryl-λ3-iodanes.
Scheme 40: α-Arylation of enolates using [bis(trifluoroacetoxy)iodo]arenes.
Scheme 41: Mechanism of the α-arylation using [bis(trifluoroacetoxy)iodo]arene.
Scheme 42: Catalytic nitrene additions mediated by [bis(acyloxy)iodo]arenes.
Scheme 43: Tandem of C(sp3)–H amination/sila-Sonogashira–Hagihara coupling.
Scheme 44: Tandem reaction using a λ3-iodane as an oxidant, a substrate and a coupling partner.
Scheme 45: Synthesis of 1,2-diarylated acrylamidines with ArI(OAc)2.
Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib
- Jingbo Yu,
- Zikun Hong,
- Xinjie Yang,
- Yu Jiang,
- Zhijiang Jiang and
- Weike Su
Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66
- corresponding coupling products 3aa and 3af in considerable yields. The scope of the reaction with respect to the olefins was also extensively investigated and encompasses acrylates 2a, acrylamides 2b and 2c, styrenes 2f–m and 2-vinylpyridine (2n). In addition, even non-activated allylbenzene 2o and
Graphical Abstract
Scheme 1: Representative pharmaceutically useful indazoles.
Scheme 2: Model Heck reaction of 3-bromo-N-methyl-1H-indazole (1a) and n-butyl acrylate (2a). (173 stainless-...
Figure 1: Investigation of additives in the Heck reaction: 1a (1.5 mmol), 2a (2.25 mmol), Pd(OAc)2 (5 mol %),...
Scheme 3: The control experiments. aTEA (1.8 mmol), silica gel (5.0 g), bPd(OAc)2 (5 mol %), PPh3 (10 mol %),...
Scheme 4: Plausible reaction pathway.
Figure 2: Influence of milling time and rotation speed on the Heck reaction: 1a (1.5 mmol), 2a (2.25 mmol), P...
Figure 3: Influence of the milling ball filling degree with different size on the Heck reaction: 1a (1.5 mmol...
Scheme 5: Examination of the substrate scope. Reaction conditions: 1 (1.5 mmol), 2 (2.25 mmol), Pd(OAc)2 (5 m...
Scheme 6: Synthesis of axitinib by mechanochemical Heck–Migita coupling. Reagents and conditions: (i) NBS, Na...
Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates
- Wengang Xu and
- Naohiko Yoshikai
Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60
- (e.g., acrylates), and is challenging with unactivated and multisubstituted alkenes [11]. The hydroarylation of alkynes does not allow for the introduction of cycloalkenyl groups because of the unavailability of the corresponding alkynes. In light of such limitations, a coupling between arene
Graphical Abstract
Scheme 1: Cobalt–NHC-catalyzed C–H alkenylation reactions with alkenyl electrophiles.
Scheme 2: Reaction of substituted pivalophenone N–H imines with 2a. aThe major regioisomer is shown (rr = reg...
Scheme 3: Reaction of 1a with various alkenyl phosphates. aA mixture of E- and Z-alkenyl phosphate (ca. 1:1) ...
Scheme 4: The cyclization of o-alkenylpivalophenone N–H imine.
Scheme 5: Proposed catalytic cycle (R = t-BuCH2, R' = P(O)(OEt)2).
CF3SO2X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF3SO2Na
- Hélène Guyon,
- Hélène Chachignon and
- Dominique Cahard
Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272
Graphical Abstract
Scheme 1: Trifluoromethylation of enol acetates by Langlois.
Scheme 2: Trifluoromethylation of (het)aryl enol acetates.
Scheme 3: Mechanism for the trifluoromethylation of enol acetates.
Scheme 4: Oxidative trifluoromethylation of unactivated olefins and mechanistic pathway.
Scheme 5: Oxidative trifluoromethylation of acetylenic substrates.
Scheme 6: Metal free trifluoromethylation of styrenes.
Scheme 7: Synthesis of α-trifluoromethylated ketones by oxytrifluoromethylation of heteroatom-functionalised ...
Scheme 8: Catalysed photoredox trifluoromethylation of vinyl azides.
Scheme 9: Oxidative difunctionalisation of alkenyl MIDA boronates.
Scheme 10: Synthesis of β-trifluoromethyl ketones from cyclopropanols.
Scheme 11: Aryltrifluoromethylation of allylic alcohols.
Scheme 12: Cascade multicomponent synthesis of nitrogen heterocycles via azotrifluoromethylation of alkenes.
Scheme 13: Photocatalytic azotrifluoromethylation of alkenes with aryldiazonium salts and CF3SO2Na.
Scheme 14: Copper-promoted intramolecular aminotrifluoromethylation of alkenes with CF3SO2Na.
Scheme 15: Oxytrifluoromethylation of alkenes with CF3SO2Na and hydroxamic acid.
Scheme 16: Manganese-catalysed oxytrifluoromethylation of styrene derivatives.
Scheme 17: Oxytrifluoromethylation of alkenes with NMP/O2 and CF3SO2Na.
Scheme 18: Intramolecular oxytrifluoromethylation of alkenes.
Scheme 19: Hydrotrifluoromethylation of styrenyl alkenes and unactivated aliphatic alkenes.
Scheme 20: Hydrotrifluoromethylation of electron-deficient alkenes.
Scheme 21: Hydrotrifluoromethylation of alkenes by iridium photoredox catalysis.
Scheme 22: Iodo- and bromotrifluoromethylation of alkenes by CF3SO2Na/I2O5 or CF3SO2Na / NaBrO3.
Scheme 23: N-methyl-9-mesityl acridinium and visible-light-induced chloro-, bromo- and SCF3 trifluoromethylati...
Scheme 24: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na / TBHP by Lipshutz.
Scheme 25: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/TBHP reported by Lei.
Scheme 26: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/(NH4)2S2O8.
Scheme 27: Metal-free carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/K2S2O8 reported by Wang.
Scheme 28: Metal-free carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/PIDA reported by Fu.
Scheme 29: Metal-free cascade trifluoromethylation/cyclisation of N-arylmethacrylamides (a) and enynes (b) wit...
Scheme 30: Trifluoromethylation/cyclisation of N-arylcinnamamides: Synthesis of 3,4-disubstituted dihydroquino...
Scheme 31: Trifluoromethylation/cyclisation of aromatic-containing unsaturated ketones.
Scheme 32: Chemo- and regioselective cascade trifluoromethylation/heteroaryl ipso-migration of unactivated alk...
Scheme 33: Copper-mediated 1,2-bis(trifluoromethylation) of alkenes.
Scheme 34: Trifluoromethylation of aromatics with CF3SO2Na reported by Langlois.
Scheme 35: Baran’s oxidative C–H trifluoromethylation of heterocycles.
Scheme 36: Trifluoromethylation of acetanilides and anilines.
Scheme 37: Trifluoromethylation of heterocycles in water.
Scheme 38: Trifluoromethylation of coumarins in a continuous-flow reactor.
Scheme 39: Oxidative trifluoromethylation of coumarins, quinolines and pyrimidinones.
Scheme 40: Oxidative trifluoromethylation of pyrimidinones and pyridinones.
Scheme 41: Phosphovanadomolybdic acid-catalysed direct C−H trifluoromethylation.
Scheme 42: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 43: Oxidative trifluoromethylation of imidazoheterocycles and imidazoles in ionic liquid/water.
Scheme 44: Oxidative trifluoromethylation of 8-aminoquinolines.
Scheme 45: Oxidative trifluoromethylation of various 8-aminoquinolines using the supported catalyst CS@Cu(OAc)2...
Scheme 46: Oxidative trifluoromethylation of the naphthylamide 70.
Scheme 47: Oxidative trifluoromethylation of various arenes in the presence of CF3SO2Na and sodium persulfate.
Scheme 48: Trifluoromethylation of electron-rich arenes and unsymmetrical biaryls with CF3SO2Na in the presenc...
Figure 1: Trifluoromethylated coumarin and flavone.
Scheme 49: Metal-free trifluoromethylation catalysed by a photoredox organocatalyst.
Scheme 50: Quinone-mediated trifluoromethylation of arenes and heteroarenes.
Scheme 51: Metal- and oxidant-free photochemical trifluoromethylation of arenes.
Scheme 52: Copper-mediated trifluoromethylation of arenediazonium tetrafluoroborates.
Scheme 53: Oxidative trifluoromethylation of aryl- and heteroarylboronic acids.
Scheme 54: Oxidative trifluoromethylation of aryl- and vinylboronic acids.
Scheme 55: Oxidative trifluoromethylation of unsaturated potassium organotrifluoroborates.
Scheme 56: Oxidative trifluoromethylation of (hetero)aryl- and vinyltrifluoroborates.
Scheme 57: Copper−catalysed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 58: Iron-mediated decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 59: Cu/Ag-catalysed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 60: I2O5-Promoted decarboxylative trifluoromethylation of cinnamic acids.
Scheme 61: Silver(I)-catalysed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 62: Copper-catalysed direct trifluoromethylation of styrene derivatives.
Scheme 63: Transition-metal-free synthesis of β-trifluoromethylated enamines.
Scheme 64: I2O5-mediated iodotrifluoromethylation of alkynes.
Scheme 65: Silver-catalysed tandem trifluoromethylation/cyclisation of aryl isonitriles.
Scheme 66: Photoredox trifluoromethylation of 2-isocyanobiphenyls.
Scheme 67: Trifluoromethylation of potassium alkynyltrifluoroborates with CF3SO2Na.
Scheme 68: N-trifluoromethylation of nitrosoarenes with CF3SO2Na (SQ: semiquinone).
Scheme 69: Trifluoromethylation of disulfides with CF3SO2Na.
Scheme 70: Trifluoromethylation of thiols with CF3SO2Na/I2O5.
Scheme 71: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/(EtO)2P(O)H/CuCl/DMSO.
Scheme 72: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/(EtO)2P(O)H/TMSCl.
Scheme 73: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PPh3/N-chlorophthalimide.
Scheme 74: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PCl3.
Scheme 75: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PCl3.
Scheme 76: Trifluoromethylsulfenylation of aryl iodides with in situ generated CuSCF3 (DMI: 1,3-dimethyl-2-imi...
Scheme 77: Pioneering trifluoromethylsulfinylation of N, O, and C-nucleophiles.
Scheme 78: Trifluoromethylsulfinylation of (1R,2S)-ephedrine (Im: imidazole; DIEA: N,N-diisopropylethylamine).
Scheme 79: Trifluoromethylsulfinylation of substituted benzenes with CF3SO2Na/CF3SO3H.
Scheme 80: Trifluoromethylsulfinylation of indoles with CF3SO2Na/P(O)Cl3.
Scheme 81: Trifluoromethylsulfinylation of indoles with CF3SO2Na/PCl3.
Scheme 82: Formation of triflones from benzyl bromides (DMA: dimethylacetamide).
Scheme 83: Formation of α-trifluoromethylsulfonyl ketones, esters, and amides.
Scheme 84: Allylic trifluoromethanesulfonylation of aromatic allylic alcohols.
Scheme 85: Copper-catalysed couplings of aryl iodonium salts with CF3SO2Na.
Scheme 86: Palladium-catalysed trifluoromethanesulfonylation of aryl triflates and chlorides with CF3SO2Na.
Scheme 87: Copper-catalysed coupling of arenediazonium tetrafluoroborates with CF3SO2Na.
Scheme 88: Synthesis of phenyltriflone via coupling of benzyne with CF3SO2Na.
Scheme 89: Synthesis of 1-trifluoromethanesulfonylcyclopentenes from 1-alkynyl-λ3-bromanes and CF3SO2Na.
Scheme 90: One-pot synthesis of functionalised vinyl triflones.
Scheme 91: Regioselective synthesis of vinyltriflones from styrenes.
Scheme 92: Trifluoromethanesulfonylation of alkynyl(phenyl) iodonium tosylates by CF3SO2Na.
Scheme 93: Synthesis of thio- and selenotrifluoromethanesulfonates.
