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Search for "lithium salt" in Full Text gives 24 result(s) in Beilstein Journal of Organic Chemistry.
Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation
- Akanksha Chhikara,
- Fan Wu,
- Navdeep Kaur,
- Prabagar Baskaran,
- Alex M. Nguyen,
- Zhichang Yin,
- Anthony H. Pham and
- Wei Li
Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122
- ; lithium salt activation; olefin oxyamination; oxazoline; Introduction Hypervalent iodine(III) reagents, also known as λ3–iodanes, have been well established and used in organic synthesis for the past decades [1][2][3][4][5]. The pioneering works of Fuchigami and Fugita, Ochiai, Kita, and later the
- hypervalent iodine catalyst precursor, Selectfluor as the oxidant, and LiBF4 as the lithium salt for hypervalent iodine activation, we were gratified to observe the formation of the desired oxazoline 3 in 59% yield as the major regioisomer in nitromethane (MeNO2) solvent (Table 1, entry 1). To further improve
- entry 7 in Table 1, resulting in the formation of the desired oxazoline product 3 in 61% isolated yield. Control reactions in the absence of either the precatalyst or oxidant afforded no product formation (Table 1, entries 11 and 12). The control reaction in the absence of the lithium salt only afforded
Graphical Abstract
Scheme 1: Hypervalent iodine-catalyzed olefin difunctionalizations background.
Figure 1: Time studies of the amide and alkene coupling. a) Iodoarene time studies: styrene (1), para-substit...
Figure 2: Amide substrate scope studies. a) Standard conditions: styrene (0.25 mmol), iodotoluene (20 mol %),...
Figure 3: Alkene substrate scope studies. a) Standard conditions: alkene (0.25 mmol), iodotoluene (20 mol %),...
Figure 4: Proposed catalytic cycle for the hypervalent iodine-catalyzed amide and alkene coupling.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors
- Grace A. Lowe
Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88
- discharge and charge the donor-containing organic phase (Figure 2A) [34]. The first solution contained an organic lithium salt and a hydrogen-evolution catalyst which could generate hydrogen via a light-driven or dark process. The second solution contained an organic chloride salt and a water oxidation
Graphical Abstract
Figure 1: Diagram comparing the two reaction pathways for sacrificial electron donors (SD) in photocatalyzed ...
Figure 2: Diagram showing water-splitting systems developed by Girault, Scanlon, and co-workers that employ i...
Figure 3: Diagram illustrating the transfer of electrons in a photocatalytic particulate suspensions Z-scheme...
Figure 4: A. Structures of the molecules represented in part B. The numbers in brackets correspond to the com...
Figure 5: A. Structures of the molecules represented in part B. The numbers in brackets correspond to the com...
Syntheses of spliceostatins and thailanstatins: a review
- William A. Donaldson
Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166
- epoxidation [37] of 5-methyl-2-methylene-4-penten-1-ol gave the epoxyalcohol 92 in 94% ee, which was oxidized to the aldehyde 93. While the addition of the lithium salt of methyl propynoate proceeded in a nondiastereoselective fashion, the use of a zirconium/silver-mediated alkynylation gave the alcohol 94
Graphical Abstract
Figure 1: Structures of spliceostatins/thailanstatins.
Scheme 1: Synthetic routes to protected (2Z,4S)-4-hydroxy-2-butenoic acid fragments.
Scheme 2: Kitahara synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 3: Koide synthesis of (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 4: Nicolaou synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 5: Jacobsen synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 6: Unproductive attempt to generate the (all-cis)-tetrahydropyranone 50.
Scheme 7: Ghosh synthesis of the C-7–C-14 (all-cis)-tetrahydropyran segment.
Scheme 8: Ghosh’s alternative route to the (all-cis)-tetrahydropyranone 50.
Scheme 9: Alternative synthesis of the dihydro-3-pyrone 58.
Scheme 10: Kitahara’s 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 11: Kitahara 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 12: Nimura/Arisawa synthesis of the C-1-phenyl segment.
Scheme 13: Ghosh synthesis of the C-1–C-6 fragment of FR901464 (1) from (R)-glyceraldehyde acetonide.
Scheme 14: Jacobsen synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 15: Koide synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 16: Ghosh synthesis of the C-1–C-5 segment 102 of thailanstatin A (7).
Scheme 17: Nicolaou synthesis of the C-1–C-9 segments of spliceostatin D (9) and thailanstatins A (7) and B (5...
Scheme 18: Ghosh synthesis of the C-1–C-6 segment 115 of spliceostatin E (10).
Scheme 19: Fragment coupling via Wittig and modified Julia olefinations by Kitahara.
Scheme 20: Fragment coupling via cross-metathesis by Koide.
Scheme 21: The Ghosh synthesis of spliceostatin A (4), FR901464 (1), spliceostatin E (10), and thailanstatin m...
Scheme 22: Arisawa synthesis of a C-1-phenyl analog of FR901464 (1).
Scheme 23: Jacobsen fragment coupling by a Pd-catalyzed Negishi coupling.
Scheme 24: Nicolaou syntheses of thailanstatin A and B (7 and 5) and spliceostatin D (9) via a Pd-catalyzed Su...
Scheme 25: The Ghosh synthesis of spliceostatin G (11) via Suzuki–Miyaura coupling.
Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose
- Lukáš Kerner and
- Paul Kosma
Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2
- lactone with the lithium salt of dimethyl methylphosphonate followed by an elimination step of the resulting hemiketal, leading to the corresponding exo- and endo-glycal derivatives. The ensuing selective monodemethylation and hydrogenolysis of the benzyl groups and reduction of the 4-azido group gave the
- lactone 4, which, however, was unstable towards chromatographic purification and used as crude material after lyophilization to remove the solvent. Coupling of 4 with the lithium salt of dimethyl methylphosphonate (5) in THF afforded the β-anomeric ketol phosphonate derivative 6 in 57% yield. The axial
Graphical Abstract
Figure 1: Modification of lipid A by ArnT.
Scheme 1: Phosphonate and glycal synthesis.
Scheme 2: Synthesis of methyl phosphonate 11 and octyl phosphonates 16 and 17.
Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands
- Tegene T. Tole,
- Johan H. L. Jordaan and
- Hermanus C. M. Vosloo
Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19
- with GxF/0.45 µm GHP membrane (PALL) was used to filter the lithium salt from the precatalyst. Experimental procedures Precatalyst synthesis: The well-established methods of Herrmann et al. [23] and Van Der Schaaf et al. [7] were used to synthesize precatalysts 6–9. This is illustrated in Scheme 2
Graphical Abstract
Figure 1: Structures of Grubbs 1 (1) and 2 (2) precatalysts.
Scheme 1: Design concepts for ruthenium alkylidene precatalysts [3].
Figure 2: Structures of Grubbs 1-type (3) and 2-type (4) pyridinyl-alcoholato precatalysts.
Figure 3: Structures of Grubbs 2-type (5) pyridinyl-alcoholato precatalysts.
Figure 4: Structures of pyridinyl-substituted Grubbs 2-type pyridinyl-alcoholato precatalysts.
Figure 5: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 6: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 7: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 8: The influence of the reaction temperature on the (a) conversion of 1-octene, (b) formation of PMPs ...
Figure 9: Geometry-optimised structures of precatalyst 9, 6 and 8.
Figure 10: An illustration of the envisaged methoxy oxygen lone pair-aromatic π-electron interaction.
Figure 11: Influence of precatalysts 6–9 and 5d on the (a) conversion of 1-octene and (b) ln([n%1-octene]) ver...
Figure 12: 1H NMR spectra of the carbene-Hα region at different time intervals of the 1-octene/7 reaction mixt...
Figure 13: 1H NMR spectra of the Hα region of the pyridine ring of the 1-octene/7 reaction mixture in toluene-d...
Scheme 2: Synthesis of pyridinyl-alcohol ligands and Grubbs 2-type pyridinyl-alcoholato complexes.
Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains
- Layal Hariss,
- Kamal Bou Hadir,
- Mirvat El-Masri,
- Thierry Roisnel,
- René Grée and
- Ali Hachem
Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208
- accessible from gem-difluoropropargylic alcohols C through a base-mediated isomerization process (Scheme 1) [26][27]. Results and Discussion The required propargylic alcohols 5a–e (type C, Scheme 1) were obtained in 27–73% yields by reaction of the lithium salt of the easily accessible gem-difluoro
Graphical Abstract
Figure 1: Representative examples of bioactive imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, imidazopyr...
Scheme 1: Retrosynthetic scheme for the preparation of our target molecules A.
Scheme 2: Synthesis of enones 6 with a gem-difluoroalkyl side chain.
Scheme 3: Synthesis of 7a.
Figure 2: Structures of 7a and 7e by X-ray crystallography analysis.
Scheme 4: One-pot synthesis of 7a.
Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds
- M. Fernanda N. N. Carvalho,
- Rudolf Herrmann and
- Gabriele Wagner
Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122
- ], or oxidised to oxaziridines used as efficient chiral oxidising reagents [13][17][18][19]. The reaction of the oxoimide 3 with two equivalents of the lithium salt of a terminal alkyne leads to compounds 4 where two alkynyl substituents, a sulfonamide and a hydroxy group are found in vicinal positions
- ) reaction of such mixed substituted compounds. Results and Discussion For the preparation of the diynes 4, a 2:1 ratio (or slightly larger for complete reaction) of the lithium salt of a terminal alkyne and of the oxoimide 3 is applied. The ratio should, however, not be increased too much. For instance
- , with benzylacetylene, the expected diyne 4e (Scheme 3d) is obtained, with only traces of monosubstituted compounds. However, with a 3:1 ratio, the main product is formed by reaction of only one equivalent of lithium salt with the C=N double bond, leaving the carbonyl group intact. In addition, the
Graphical Abstract
Scheme 1: Synthesis of 3-oxo-camphorsulfonylimine (3) [13,15] and its bis-alkynyl derivatives 4 from camphor-10-sulf...
Scheme 2: Reactions of bis-alkynyl camphor derivative 4a with TiCl4 and with Br2, respectively.
Scheme 3: Reactions of bis-alkynylcamphor derivatives 4a–e with catalytic amounts of PtCl2(PhCN)2.
Scheme 4: Attempted selective synthesis of 3-alkynyl derivatives via sulfonylimine reduction of oxoimide 3.
Scheme 5: Selective synthesis of 2-alkynyl derivatives by protection of the 3-oxo group as an acetal.
Scheme 6: Selective synthesis of 2-alkynyl derivatives by protection of the 3-oxo group as an imine.
Scheme 7: Synthesis of the bis-alkynyl derivatives bearing different alkyne substituents and their platinum-c...
Scheme 8: Proposed mechanism of the platinum-catalysed cycloisomerisation.
Substitution of fluorine in M[C6F5BF3] with organolithium compounds: distinctions between O- and N-nucleophiles
- Anton Yu. Shabalin,
- Nicolay Yu. Adonin and
- Vadim V. Bardin
Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69
- prepared by metathesis of 1-K with LiHal (Hal = Cl, Br, I) in an approapriate solvent (Scheme 8). After determination of the salt concentration by 19F NMR, 1-Li was used in DME without isolation. When the metathesis was performed in MeCN, the lithium salt was isolated from MeCN as solid solvate Li[C6F5BF3
- BuLi and PhC≡CLi. Indeed, heating 1-K with LiHal (Hal = I, Br, or Cl) in DME at 55–70 °C leads to the formation of C6F5H. [Bu4N][C6F5BF3] reacts with LiI in diglyme in a similar way. Because the cations K+ or Bu4N+ are replaced with Li+ in all cases, the reactions proceed via the lithium salt. Actually
- absence of other salts the lithium salt is relatively stable. This phenomenon was explained by the formation of a dinuclear methoxy-bridged borate intermediate [C6F5B(OMe)2–(μ-OMe)–B(OMe)2C6F5]− (B) followed the migration of both the aryl and the methoxy groups. If Li+ and [C6F5B(OMe)3]− form a contact
Graphical Abstract
Scheme 1: Preparation of polyfluoroorganotrifluoroborates.
Scheme 2: Interaction of K[C6F5BF3] (1-K) with methyllithium (byproducts of hydrodeboration are not depicted)....
Scheme 3: Interaction of M[C6F5BF3] (1-M) with butyllithium (byproducts of hydrodeboration are not depicted).
Scheme 4: Interaction of K[C6F5BF3] (1-K) with phenyllithium (byproducts of hydrodeboration are not depicted)....
Scheme 5: Hydrodeboration of 6-K, 7-K, 8-K and 9-K in MeOH.
Scheme 6: Hydrodeboration of 1-K, 10-K and 11-K in methyl cellosolve.
Scheme 7: Hydrodeboration of 10-K, 11-K, 12-K and 13-K in MeOH.
Scheme 8: Preparation of 1-Li and 1-N.
Scheme 9: Formation of 2-R-tetrafluorophenyltrifluoroborates.
Scheme 10: Interaction between C6F5BF3− and PhLi.
Scheme 11: Interaction of 1-K with MeONa.
Scheme 12: Interaction of M[RC6F5BF3] with lithium halides.
Scheme 13: Assumed role of lithium halides.
Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update
- Bin Yu,
- Hui Xing,
- De-Quan Yu and
- Hong-Min Liu
Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98
- effects on the enantioselectivity. Compared to acetone and cycloheptanone, good enantioselectivities were obtained for cyclohexanone. Based on the previously observed catalytic performance of amino acid metal salts in asymmetric catalysis, Luo and co-workers reported that phenylalanine lithium salt (cat
- . 8) can efficiently catalyze the aldol reaction of substituted isatins with ketones, allowing facile access to the 3-hydroxyoxindoles in moderate to good yields (73–97% yield) and with good enantioselectivity (66–90% ee, Scheme 21) [37]. The phenylalanine lithium salt was easily prepared from
Graphical Abstract
Figure 1: 3-Hydroxyoxindole-containing natural products and biologically active molecules.
Scheme 1: Chiral CNN pincer Pd(II) complex 1 catalyzed asymmetric allylation of isatins.
Scheme 2: Asymmetric allylation of ketimine catalyzed by the chiral CNN pincer Pd(II) complex 2.
Scheme 3: Pd/L1 complex-catalyzed asymmetric allylation of 3-O-Boc-oxindoles.
Scheme 4: Cu(OTf)2-catalyzed asymmetric direct addition of acetonitrile to isatins.
Scheme 5: Chiral tridentate Schiff base/Cu complex catalyzed asymmetric Friedel–Crafts alkylation of isatins ...
Scheme 6: Guanidine/CuI-catalyzed asymmetric alkynylation of isatins with terminal alkynes.
Scheme 7: Asymmetric intramolecular direct hydroarylation of α-ketoamides.
Scheme 8: Plausible catalytic cycle for the direct hydroarylation of α-ketoamides.
Scheme 9: Ir-catalyzed asymmetric arylation of isatins with arylboronic acids.
Scheme 10: Enantioselective decarboxylative addition of β-ketoacids to isatins.
Scheme 11: Ruthenium-catalyzed hydrohydroxyalkylation of olefins and 3-hydroxy-2-oxindoles.
Scheme 12: Proposed catalytic mechanism and stereochemical model.
Scheme 13: In-catalyzed allylation of isatins with stannylated reagents.
Scheme 14: Modified protocol for the synthesis of allylated 3-hydroxyoxindoles.
Scheme 15: Hg-catalyzed asymmetric allylation of isatins with allyltrimethylsilanes.
Scheme 16: Enantioselective additions of organoborons to isatins.
Scheme 17: Asymmetric aldol reaction of isatins with cyclohexanone.
Scheme 18: Enantioselective aldol reactions of aliphatic aldehydes with isatin derivatives and the plausible t...
Scheme 19: Enantioselective aldol reaction of isatins and 2,2-dimethyl-1,3-dioxan-5-one.
Scheme 20: Asymmetric aldol reactions between ketones and isatins.
Scheme 21: Phenylalanine lithium salt-catalyzed asymmetric synthesis of 3-alkyl-3-hydroxyoxindoles.
Scheme 22: Aldolization between isatins and dihydroxyacetone derivatives.
Scheme 23: One-pot asymmetric synthesis of convolutamydine A.
Scheme 24: Asymmetric aldol reactions of cyclohexanone and acetone with isatins.
Scheme 25: Aldol reactions of acetone with isatins.
Scheme 26: Aldol reactions of ketones with isatins.
Scheme 27: Enantioselective allylation of isatins.
Scheme 28: Asymmetric aldol reaction of trifluoromethyl α-fluorinated β-keto gem-diols with isatins.
Scheme 29: Plausible mechanism proposed for the asymmetric aldol reaction.
Scheme 30: Asymmetric aldol reaction of 1,1-dimethoxyacetone with isatins.
Scheme 31: Enantioselective Friedel-Crafts reaction of phenols with isatins.
Scheme 32: Enantioselective addition of 1-naphthols with isatins.
Scheme 33: Enantioselective aldol reaction between 3-acetyl-2H-chromen-2-ones and isatins.
Scheme 34: Stereoselective Mukaiyama–aldol reaction of fluorinated silyl enol ethers with isatins.
Scheme 35: Asymmetric vinylogous Mukaiyama–aldol reaction between 2-(trimethylsilyloxy)furan and isatins.
Scheme 36: β-ICD-catalyzed MBH reactions of isatins with maleimides.
Scheme 37: β-ICD-catalyzed MBH reactions of 7-azaisatins with maleimides and activated alkenes.
Scheme 38: Enantioselective aldol reaction of isatins with ketones.
Scheme 39: Direct asymmetric vinylogous aldol reactions of allyl ketones with isatins.
Scheme 40: Enantioselective aldol reactions of ketones with isatins.
Scheme 41: The MBH reaction of isatins with α,β-unsaturated γ-butyrolactam.
Scheme 42: Reactions of tert-butyl hydrazones with isatins followed by oxidation.
Scheme 43: Aldol reactions of isatin derivatives with ketones.
Scheme 44: Enantioselective decarboxylative cyanomethylation of isatins.
Scheme 45: Catalytic kinetic resolution of 3-hydroxy-3-substituted oxindoles.
Scheme 46: Lewis acid catalyzed Friedel–Crafts alkylation of 3-hydroxy-2-oxindoles with electron-rich phenols.
Scheme 47: Lewis acid catalyzed arylation of 3-hydroxyoxindoles with aromatics.
Scheme 48: Synthetic application of 3-arylated disubstituted oxindoles in the construction of core structures ...
Scheme 49: CPA-catalyzed dearomatization and arylation of 3-indolyl-3-hydroxyoxindoles with tryptamines and 3-...
Scheme 50: CPA-catalyzed enantioselective decarboxylative alkylation of β-keto acids with 3-hydroxy-3-indolylo...
Scheme 51: BINOL-derived imidodiphosphoric acid-catalyzed enantioselective Friedel–Crafts reactions of indoles...
Scheme 52: CPA-catalyzed enantioselective allylation of 3-indolylmethanols.
Scheme 53: 3-Indolylmethanol-based substitution and cycloaddition reactions.
Scheme 54: CPA-catalyzed asymmetric [3 + 3] cycloaddtion reactions of 3-indolylmethanols with azomethine ylide...
Scheme 55: CPA-catalyzed three-component cascade Michael/Pictet–Spengler reactions of 3-indolylmethanols and a...
Scheme 56: Acid-promoted chemodivergent and stereoselective synthesis of diverse indole derivatives.
Scheme 57: CPA-catalyzed asymmetric formal [3 + 2] cycloadditions.
Scheme 58: CPA-catalyzed enantioselective cascade reactions for the synthesis of C7-functionlized indoles.
Scheme 59: Lewis acid-promoted Prins cyclization of 3-allyl-3-hydroxyoxindoles with aldehydes.
Scheme 60: Ga(OTf)3-catalyzed reactions of allenols and phenols.
Scheme 61: I2-catalyzed construction of pyrrolo[2.3.4-kl]acridines from enaminones and 3-indolyl-3-hydroxyoxin...
Scheme 62: CPA-catalyzed asymmetric aza-ene reaction of 3-indolylmethanols with cyclic enaminones.
Scheme 63: Asymmetric α-alkylation of aldehydes with 3-indolyl-3-hydroxyoxindoles.
Scheme 64: Organocatalytic asymmetric α-alkylation of enolizable aldehydes with 3-indolyl-3-hydroxyoxindoles a...
Fe(II)/Et3N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives
- Ekaterina E. Galenko,
- Olesya A. Tomashenko,
- Alexander F. Khlebnikov,
- Mikhail S. Novikov and
- Taras L. Panikorovskii
Beilstein J. Org. Chem. 2015, 11, 1732–1740, doi:10.3762/bjoc.11.189
- 110 °C for 24 h. Then reaction mixture was evaporated to dryness and water (5 mL) was added. The suspension was filtered, the solid was washed with water (2 × 5 mL) and thoroughly dried to obtain lithium salt 14b in quantitive yield. To convert the lithium salt 14b into 6b trichloroacetic acid (35 mg
- , 0.212 mmol, 1 equiv) was added to a suspension of the lithium salt in water (5 mL). The suspension was sonicated for 5 min, stirred for 1 h and filtered. The solid was washed with water and dried to obtain 6b as a colorless solid, mp 205–207 °C, yield 79 mg, 98%. 1Н NMR (DMSO-d6) δ 3.82 (s, 3H), 7.11
Graphical Abstract
Scheme 1: The formation and possible tautomeric equilibria of 2-methoxycarbonyl- and 2-carboxy-3-(1H-imidazol...
Scheme 2: FeCl2/Et3N-catalyzed domino sequence leading to 5-alkoxycarbonylpyrrol-3-ylimidazolium salts 1.
Scheme 3: The synthesis of methyl 4-(1H-imidazol-1-yl)-1H-pyrrole-2-carboxylates 12.
Scheme 4: The hydrolysis of ylide 2a and bromide 1b.
Figure 1: Molecular structure of compound 6b (CCDC 1406417). Carbon, nitrogen and oxygen atoms are grey, blue...
First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine
- Paweł Borowiecki,
- Daniel Paprocki and
- Maciej Dranka
Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322
- conditions, failed as well leading to complex mixtures. The above mentioned drawbacks were finally overcome by using the lithium salt of phenothiazine 1 for the oxirane 2 ring opening as it was described at the beginning of this paragraph. To obtain racemic esters (±)-4a–c which are required for robust
Graphical Abstract
Scheme 1: Chemoenzymatic synthesis of enantioenriched enantiomers of promethazine 9 and ethopropazine 10. Rea...
Figure 1: Dependence of optical purities (% ee) of (R)-(−)-6a (red curve, ■) and (S)-(+)-5 (blue curve, ▲) on...
Scheme 2: Assignment of the stereochemistry of enantiopure alcohol (+)-5 resulting from derivatization with (R...
Figure 2: Description of substituents for determination of the absolute configuration of (+)-5 and ΔδRS value...
Figure 3: 1H NMR (CDCl3, 400 MHz) spectra of the (R)-MPA 11 (red colored line) and (S)-MPA and 12 (blue color...
Figure 4: An ORTEP plot of (S)-(+)-1-(10H-phenothiazin-10-yl)propan-2-ol (S)-(+)-5. The following crystal str...
Scheme 3: Amination of optically active bromo derivatives (R)-(+)-8 or (S)-(−)-8 in toluene.
Scheme 4: Amination of optically active bromo derivatives (R)-(+)-8 or (S)-(−)-8 in methanol.
Scheme 5: The proposed reaction mechanism for amination of optically active (S)-(−)-8 in methanol.
Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants§
- Rudolf Knorr,
- Thomas Menke,
- Johannes Freudenreich and
- Claudio Pires
Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28
- ketene incorporated KOH to afford the potassium salt of 1,1,3,3-tetramethylindan-2-carboxylic acid (the product of a formal hydrolysis). The lithium salt of this key acid is able to acylate aryllithium compounds, furnishing one-sidedly overcrowded ketones along with the corresponding tertiary alcohols
Graphical Abstract
Scheme 1: 1,1,3,3-Tetramethylindane derivatives are preferable.
Scheme 2: “Hydrolysis” of 6, and the KOR/dimsyl-K (11) system.
Scheme 3: Proposed carbenoid pathway from 6 to acid 10 and dimethyl sulfide (Me2S) in DMSO as the solvent.
Scheme 4: Proposed pathway to the main side-product 23 formed by nucleophilic addition of 11 to C-2 of 6.
Scheme 5: Possible course of the carbenoid chain reaction of 12 with DMSO and the α,α-dichloroalkene 6.
Scheme 6: Synthesis of the one-sidedly overcrowded descendants 38, 39, and 42.
Synthesis of 3,4-dihydro-1,8-naphthyridin-2(1H)-ones via microwave-activated inverse electron-demand Diels–Alder reactions
- Salah Fadel,
- Youssef Hajbi,
- Mostafa Khouili,
- Said Lazar,
- Franck Suzenet and
- Gérald Guillaumet
Beilstein J. Org. Chem. 2014, 10, 282–286, doi:10.3762/bjoc.10.24
- THF in the presence of EDCI and DMAP. The corresponding amides 2–5 were obtained in excellent yields (Scheme 2). The results are shown in Table 1. Preparation of N-substituted N-triazinylpent-4-ynamides The nucleophilic substitution of the methylsulfonyl leaving group from 1 by the lithium salt of
Graphical Abstract
Scheme 1: (a) MeI, EtOH, reflux, 3 h (87%); (b) phenylglyoxal, Na2CO3, H2O, 5 °C, 6 h (96%); (c) MCPBA, CH2Cl2...
Scheme 2: Coupling of pent-4-ynoic acid with different amines. Conditions: (a) EDCI, DMAP, THF, rt, 36 h.
Scheme 3: Reaction of triazine 1 with different pent-4-ynamides. Conditions: n-BuLi, THF, −30 °C, 2 h.
Scheme 4: Reaction of triazines 6–9 under microwave irradiation. Conditions: Chorobenzene, 220 °C, 1 h.
Scheme 5: Preparation of aryl-N-triazinylpentynamides. Conditions: CuI (10 mol %), Pd(PPh3)2Cl2 (5 mol %), DM...
Scheme 6: Preparation of 3,4-dihydro-1,8-naphthridin-2(1H)-ones. Conditions: Chlorobenzene, 220 °C, 1 h.
Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products
- Mikko Passiniemi and
- Ari M.P. Koskinen
Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300
- many others have demonstrated that there is practically no epimerization of the α-carbon center of 1 during the addition reaction [38]. While working on the synthesis of thymine polyoxin C, Garner coupled the lithium salt of ethyl propiolate with (R)-1 (Scheme 9) in HMPT/THF at −78 °C. The reaction was
Graphical Abstract
Figure 1: Structures of limonene, carvone and thalidomide.
Figure 2: Structure of Garner’s aldehyde.
Scheme 1: (a) i) Boc2O, 1.0 N NaOH (pH >10), dioxane, +5 °C → rt; ii) MeI, K2CO3, DMF, 0 °C → rt (86% over tw...
Scheme 2: (a) AcCl, MeOH, 0 °C → reflux (99%); (b) i) (Boc)2O, Et3N, THF, 0 °C → rt → 50 °C (89%); ii) Me2C(O...
Scheme 3: (a) LiAlH4, THF, rt (93–96%); (b) (COCl)2, DMSO, iPr2NEt, CH2Cl2, −78 °C → −55 °C (99%).
Scheme 4: The Koskinen procedure for the preparation of Garner’s aldehyde. (a) i) AcCl, MeOH, 0 °C → 50 °C (9...
Scheme 5: Burke’s synthesis of Garner’s aldehyde. BDP - bis(diazaphospholane).
Figure 3: Structures of some iminosugars (7, 9), peptide antibiotics (8) and sphingosine (10) and pachastriss...
Scheme 6: Use of Garner’s aldehyde 1 in multistep synthesis.
Scheme 7: Explanation of the anti- and syn-selectivity in the nucleophilic addition reaction.
Scheme 8: Herold’s method: (a) Lithium 1-pentadecyne, HMPT, THF, −78 °C (71%); (b) Lithium 1-pentadecyne, ZnBr...
Scheme 9: (a) Ethyl lithiumpropiolate, HMPT, THF, −78 °C; (b) (S)- or (R)-MTPA, DCC, DMAP, THF, rt (18, 81%) ...
Scheme 10: Coleman’s selectivity studies and their transition state model for the co-ordinated delivery of the...
Scheme 11: (a) PhMgBr, THF, −78 °C → 0 °C [62] or (a) PhMgBr, Et2O, 0 °C [63].
Scheme 12: (a) cat. RhCl3·3H2O, cat. 26, NaOMe, Ph-B(OH)2, aq DME, 80 °C (24, 71%); (b) cat. RhCl3·3H2O, cat. ...
Scheme 13: Lithiated dithiane (3 equiv), CuI (0.3 equiv), BF3·Et2O (6 equiv), THF, −50 °C, 12 h (70%).
Scheme 14: Addition reaction reported by Lam et al. (a) 1-Hexyne, n-BuLi, THF, −15 °C or −40 °C.
Scheme 15: (a) n-BuLi, HMPT, toluene, −78 °C → rt (85%); (b) n-BuLi, ZnCl2, toluene/Et2O, −78 °C → rt (65%).
Scheme 16: (a) n-BuLi, 34, THF, −40 °C [69]; (b) n-BuLi, 35, THF, −78 °C → rt (80%) [70]; (c) n-BuLi, 35, HMPT, THF, −...
Scheme 17: (a) cat. Rh(acac)(CO)2, 42, THF, 40 °C (74%).
Scheme 18: (a) 1-PropynylMgBr, CuI, THF, Me2S, −78 °C (95%); (b) Ethynyltrimethylsilane, EtMgBr, CuI, THF, Me2...
Scheme 19: (a) cat. 50, toluene, 0 °C (52%); (b) cat. 51, toluene, 0 °C (51%); (c) cat. 52, toluene, 0 °C (50%...
Scheme 20: (a) (iPr)3SiH, cat. Ni(COD)2, dimesityleneimidazolium·HCl, t-BuOK, THF, rt.
Scheme 21: (a) Cp2Zr(H)Cl, cat. AgAsF6, CH2Cl2, rt; (b) Cp2Zr(H)Cl, 1-pentadecyne, cat. ZnBr2 in THF for anti-...
Scheme 22: (a) i) 31, n-BuLi, THF, −78 °C; ii) (S)-1, THF, −78 °C; (b) Red-Al, THF, 0 °C.
Scheme 23: (a) 61, n-BuLi, DMPU, toluene, −78 °C, then (S)-1, toluene, −95 °C (57%); (b) 61, n-BuLi, ZnCl2, to...
Scheme 24: Olefin A as an intermediate in natural product synthesis.
Scheme 25: (a) Ph3(Me)PBr, KH, benzene (66%, rac-64) or (b) AlMe3, Zn, CH2I2, THF (76%) [101]; (c) Ph3(Me)PBr, n-Bu...
Scheme 26: (a) Benzene, rt (82%) [108]; (b) K2CO3, MeOH (85%) [89]; (c) iPrOH, [Ir(COD)Cl]2, PPh3, THF, rt (81%) [114].
Scheme 27: Mechanism of the Still–Gennari modification of the HWE reaction leading to both olefin isomers.
Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains
- Assaad Nasr El Dine,
- Ali Khalaf,
- Danielle Grée,
- Olivier Tasseau,
- Fares Fares,
- Nada Jaber,
- Philippe Lesot,
- Ali Hachem and
- René Grée
Beilstein J. Org. Chem. 2013, 9, 1943–1948, doi:10.3762/bjoc.9.230
- bearing a CF3 group on the triple bond could be isomerised to the corresponding enones. In that case, Et3N proved to be sufficient as a catalyst to perform this transformation [28]. The required starting propargylic alcohols were obtained by a reaction of the lithium salt of easily available gem-difluoro
Graphical Abstract
Scheme 1: Strategy towards the target molecules.
Scheme 2: Synthesis of enones with a gem-difluoroalkyl side chain.
Scheme 3: Synthesis of pyrazolines with a gem-difluoro side chain.
Scheme 4: One-pot synthesis of pyrazolines with a gem-difluoro side chain.
Scheme 5: Synthesis of pyrrolines with a gem-difluoro alkyl side chain.
Scheme 6: One-pot synthesis of pyrrolines with a gem-difluoro side chain.
Scheme 7: Pd-catalyzed coupling reactions towards chemical libraries of pyrazolines with a gem-difluoro side ...
Scheme 8: Pd-catalyzed coupling reactions towards chemical libraries of pyrrolines with a gem-difluoro side c...
Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization
- Guillaume Moreira,
- Laurence Charles,
- Mohamed Major,
- Florence Vacandio,
- Yohann Guillaneuf,
- Catherine Lefay and
- Didier Gigmes
Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181
- conditions to perform an SG1-based nitroxide-mediated graft polymerization from cellobiose have been established, the next stage of this work will be the modification of cellulose and cellulose derivatives by NMP. Keywords: ESR; glucose; lithium salt; nitroxide; SG1; stability; Introduction With the rising
- solvents (DMA, DMF, MeOH and t-BuPh) without lithium salt was first investigated by ESR (Figure 5). In accordance with previous experiments, SG1 solutions in DMA, DMF, MeOH or t-BuPh (1.5 × 10−2 mol·L−1) were heated at 120 °C and then diluted in t-BuPh for ESR analysis at 25 °C. The SG1 degradation is
- influence of the lithium salt concentration (LiCl or LiBr) was then investigated at 4.5 and 10 wt % in DMF and DMA (Figure 6). Figure 6 clearly proves that irrespective of the counter ion (Cl− or Br−), SG1 was totally consumed within 1 hour with 4.5 or 10 wt % of lithium salt in DMF or DMA. In contrast to
Graphical Abstract
Figure 1: Structure of the SG1, TEMPO and DBN nitroxides and the BlocBuilder MA alkoxyamine.
Figure 2: Key equilibrium between active and dormant species involved in the nitroxide-mediated (NMP) polymer...
Figure 3: Degradation of the SG1 nitroxide versus time in the presence of 0 (empty stars), 1 (filled squares)...
Figure 4: Degradation of the SG1 (triangles) and TEMPO (squares) nitroxides versus time in the presence of 0 ...
Figure 5: Degradation of the SG1 nitroxide versus time in DMA (filled squares), DMF (filled triangles), MeOH ...
Figure 6: Degradation of the SG1 nitroxide versus time in the presence of 0% of lithium salt in DMA (empty sq...
Figure 7: Degradation of the TEMPO nitroxide versus time in DMA in the presence of 0% lithium salt (empty squ...
Figure 8: NMP of styrene initiated by the BlocBuilder MA alkoxyamine at 120 °C in DMA without LiCl salt. (a) ...
Scheme 1: Synthesis of the cellobiose and SG1-based alkoxyamine (cello-SG1). The shown regioisomer exhibits a...
Figure 9: (a) Evolution of the number-average molar mass (Mn: filled symbol, linear fit: dash lines) and poly...
Scheme 2: (Reversible) redox system of nitroxide.
Figure 10: Cyclic voltammograms in DMF of (a) SG1 (10−2 M)/ NaClO4 (10−1 M) and (b) LiCl (10−2 M)/TBAPF6 (10−1...
Figure 11: Cyclic voltammograms of DMF/4.5 wt % LiBr solution heated at 80 °C for 30 min (plain line) and 14 h...
Scheme 3: Hydrolysis of DMA in the presence of LiCl.
Scheme 4: Disproportionation of nitroxide 1 by acid treatment.
Figure 12: Degradation of the nitroxides (SG1 and TEMPO) in the presence of HCl. (a) TEMPO ESR signal in the p...
Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO4
- Leandro Lara de Carvalho,
- Robert Alan Burrow and
- Vera Lúcia Patrocinio Pereira
Beilstein J. Org. Chem. 2013, 9, 838–845, doi:10.3762/bjoc.9.96
- chiral nitroalkenes 5a–c with EVE and MA, acrylonitrile (AN) or methyl vinyl ketone (MVK) were carried out using lithium salt solutions (Table 2). Initially, the reactivity of 5d in lithium perchlorate solution 4.7 M in THF/H2O (3:1) (henceforth LPTW), (Table 2, entry 1) was investigated. A mixture of
- related). The cycloadditions with 5a–c were performed in concentrated lithium salt solutions following similar protocols described in the literature in which lithium perchlorate 5.0 M in diethyl ether (LPDE) was employed successful as a promoter in Diels–Alder reactions. This solution was found to be a
- good reaction medium causing a large enhancement in the reaction rate. Moreover, the role of the lithium salt solution in the cycloaddition reactions is still controversial and has been the subject of discussion. The increase of the solvent internal pressure, caused by the presence of lithium salt, and
Graphical Abstract
Scheme 1: Reactivity of nitroalkenes and/or their respective nitronates in cycloaddition reactions.
Scheme 2: Synthetic route toward the chiral (S,E)-γ-aminated nitroalkenes 5a–c and their 1,3-diamine derivati...
Figure 1: ORTEP for nitroso acetal 11b.
Figure 2: 1D NOESY correlation between H2, H3a, H4 and H6 for all nitroso acetals.
Scheme 3: Transition-state models to stereoselective approaches in the multicomponent cycloadditions of 5a–c.
Scheme 4: Hydrogenolysis of 9c to pyrrolizidin-3-one 14c.
Fifty years of oxacalix[3]arenes: A review
- Kevin Cottet,
- Paula M. Marcos and
- Peter J. Cragg
Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22
- ) complex [56]. The structure was dimeric; each macrocycle was present as the trianion bound to the titanium by all three oxygens and pulled slightly into the cavity by iPrO−. The paper also reported the result of a reaction between the lithium salt of 3b and vanadyl chloride (VOCl3). Based on powder
Graphical Abstract
Figure 1: Calixarenes and expanded calixarenes: p-tert-Butylcalix[4]arene (1), p-tert-butyldihomooxacalix[4]a...
Figure 2: Conventional nomenclature for oxacalix[n]arenes.
Scheme 1: Synthesis of oxacalix[3]arenes: (i) Formaldehyde (37% aq), NaOH (aq), 1,4-dioxane; glacial acetic a...
Figure 3: p-tert-Butyloctahomotetraoxacalix[4]arene (4a) [16].
Figure 4: X-ray crystal structure of 3a showing phenolic hydrogen bonding (IUCr ID AS0508) [17].
Scheme 2: Stepwise synthesis of asymmetric oxacalix[3]arenes: (i) MOMCl, Adogen®464; (ii) 2,2-dimethoxypropan...
Figure 5: X-ray crystal structure of heptahomotetraoxacalix[3]arene 5 (CCDC ID 166088) [21].
Scheme 3: Oxacalix[3]arene synthesis by reductive coupling: (i) Me3SiOTf, Et3SiH, CH2Cl2; R1, R2 = I, Br, ben...
Scheme 4: Oxacalix[3]naphthalene: (i) HClO4 (aq), wet CHCl3 (R = tert-butyl, 6a, H, 6b) [20].
Figure 6: Conformers of 3a.
Scheme 5: Origin of the 25:75 cone:partial-cone statistical distribution of O-substituted oxacalix[3]arenes (p...
Scheme 6: Synthesis of alkyl ethers 7–10: (i) Alkyl halide, NaH, DMF [24].
Scheme 7: Synthesis of a pyridyl derivative 11a: (i) Picolyl chloride hydrochloride, NaH, DMF [26,27].
Figure 7: X-ray crystal structure of partial-cone 11a (CCDC ID 150580) [26].
Scheme 8: Lower-rim ethyl ester synthesis: (i) Ethyl bromoacetate, NaH, t-BuOK or alkali metal carbonate, THF...
Scheme 9: Forming chiral receptor 13: (i) Ethyl bromoacetate, NaH, THF; (ii) NaOH, H2O/1,4-dioxane; (iii) S-P...
Figure 8: X-ray crystal structure of 16 (IUCr ID PA1110) [32].
Scheme 10: Lower rim N,N-diethylamide 17a: (i) N,N-Diethylchloroacetamide, NaH, t-BuOK or alkali metal carbona...
Scheme 11: Capping the lower rim: (i) N,N-Diethylchloroacetamide, NaH, THF; (ii) NaOH, H2O/1,4-dioxane; (iii) ...
Figure 9: X-ray crystal structure of 18 (CCDC ID 142599) [33].
Scheme 12: Extending the lower rim: (i) Glycine methyl ester, HOBt, dicyclohexycarbodiimide (DCC), CH2Cl2; (ii...
Scheme 13: Synthesis of N-hydroxypyrazinone derivative 23: (i) 1-[3-(Dimethylamino)propyl]-3-ethylcarbodiimide...
Scheme 14: Synthesis of 24: (i) 1-Adamantyl bromomethyl ketone, NaH, THF [39].
Scheme 15: Synthesis of 25 and 26: (i) (Diphenylphosphino)methyl tosylate, NaH, toluene; (ii) phenylsilane, to...
Figure 10: X-ray crystal structure of 27 in the partial-cone conformer (CCDC ID SUP 90399) [41].
Scheme 16: Synthesis of strapped oxacalix[3]arene derivatives 28 and 29: (i) N,N’-Bis(chloroacetyl)-1,2-ethyle...
Figure 11: A chiral oxacalix[3]arene [45].
Figure 12: X-ray crystal structure of asymmetric oxacalix[3]arene 30 incorporating t-Bu, iPr and Et groups (CC...
Scheme 17: Reactions of an oxacalix[3]arene incorporating an upper-rim Br atom with (i) Pd(OAc)2, PPh3, HCO2H,...
Scheme 18: Synthesis of acid 39: (i) NaOH, EtOH/H2O, HCl (aq) [47].
Figure 13: Two forms of dimeric oxacalix[3]arene 40 [47].
Scheme 19: Capping the upper rim: (i) t-BuLi, THF, −78 °C; (ii) NaBH4, THF/EtOH; (iii) 1,3,5-tris(bromomethyl)...
Figure 14: Oxacalix[3]arene capsules 46 and 47 formed through coordination chemistry [52,53].
Figure 15: X-ray crystal structure of the 3b-vanadyl complex (CCDC ID 240185) [57].
Scheme 20: Effect of Ti(IV)/SiO2 on 3a: (i) Ti(OiPr)4, toluene; (ii) triphenylsilanol, toluene; (iii) partiall...
Figure 16: X-ray crystal structures of oxacalix[3]arene complexes with rhenium: 3b∙Re(CO)3 (CCDC ID 620981, le...
Figure 17: X-ray crystal structure of the La2·3a2 complex (CSD ID TIXXUT) [60].
Figure 18: X-ray crystal structures of [3a∙UO2]− with a cavity-bound cation (CCDC ID 135575, left) and without...
Figure 19: X-ray crystal structure of a supramolecule comprising two [3g·UO2]− complexes that encapsulate a di...
Figure 20: X-ray crystal structure of oxacalix[3]arene 49 capable of chiral selectivity (CSD ID HIGMUF) [65].
Figure 21: The structure of derivative 50 incorporating a Reichardt dye [66].
Figure 22: Phosphorylated oxacalix[3]arene complexes with transition metals: (Left to right) 26∙Au, 26∙Mo(CO)3...
Figure 23: X-ray crystal structure of [17a·HgCl2]2 (CCDC ID 168653) [69].
Figure 24: X-ray crystal structures of 3f with C60 (CCDC ID 182801, left) [76] and a 1,4-bis(9-fluorenyl) C60 deri...
Figure 25: X-Ray crystal structure of 3i and 6a encapsulating C60 (CCDC ID 102473 and 166077) [23,79].
Figure 26: A C60 complexing cationic oxacalix[3]arene 51 [81].
Figure 27: An oxacalix[3]arene-C60 self-associating system 53 [87].
Scheme 21: Synthesis of fluorescent pyrene derivative 55: (i) Propargyl bromide, acetone; (ii) CuI, 1-azidomet...
Scheme 22: Synthesis of responsive rhodamine derivative 57: (i) DCC, CH2Cl2 [91].
Scheme 23: Synthesis of nitrobenzyl derivative 58: (i) 1-Bromo-4-nitrobenzyl acetate, K2CO3, refluxing acetone...
Figure 28: X-ray crystal structure of [Na2∙17a](PF6)2 (CCDC ID 116656) [97].
Synthetic approaches to multifunctional indenes
- Neus Mesquida,
- Sara López-Pérez,
- Immaculada Dinarès and
- Ermitas Alcalde
Beilstein J. Org. Chem. 2011, 7, 1739–1744, doi:10.3762/bjoc.7.204
- -indenyl)acetamides as key intermediates. Although several multistep synthetic approaches can be applied to obtain these advanced intermediates, we describe herein their preparation by an aldol-type reaction between 5-nitroindan-1-ones and the lithium salt of N,N-disubstituted acetamides, followed
- nitroindanones 5 and the lithium salt of ethyl acetate [18]. The present work deals with the alternative synthetic route B, which relies on the direct formation of the advanced (3-indenyl)acetamides 3 from nitroindanone 5 and shortens the synthetic sequence to two steps. The aldol-type reaction of indanone 5
- recently reported that the reaction of 2-methylindanone 6 with the lithium salt of ethyl acetate (generated in situ by the reaction of lithium hexamethyldisilazide with ethyl acetate), immediately followed by dehydration and hydrolysis/isomerization, afforded the acetic acid 7 with an improved yield of 74
Graphical Abstract
Scheme 1: Retrosynthetic pathways to 3,5-disubstituted indenes bearing two functional groups: Indenylsulfonam...
Scheme 2: Reagents and conditions: (i) (a) EtOAc, LHMDS, THF, −78 °C, (b) H2SO4, H2O, 60 °C [18]; (ii) (a) SOCl2,...
Scheme 3: Reagents and conditions: (i) (a) EtOAc, LHMDS, THF, −78 °C, (b) H2SO4, H2O, 60 °C [18]; (ii) (a) SOCl2,...
Scheme 4: Reagents and conditions: (i) KNO3, H2SO4, −5 °C; (ii) (a) EtOAc, LHMDS, THF, −78 °C, (b) H2SO4, H2O...
Figure 1: Key NMR responses for compounds 17, 19 and 23: 1D NOESY experiments.
Recent advances in the development of alkyne metathesis catalysts
- Xian Wu and
- Matthias Tamm
Beilstein J. Org. Chem. 2011, 7, 82–93, doi:10.3762/bjoc.7.12
- confirmed by our independent synthesis of the tungsten benzylidyne complex 39 (Scheme 9), which can be isolated in high yield as a yellow crystalline solid from the reaction of the tribromide [PhC≡WBr3(dme)] (dme = 1,2-dimethoxyethane) with the lithium salt of the silanol (t-BuO)3SiOH [88]. Since this
Graphical Abstract
Scheme 1: Alkyne metathesis based on the Katz mechanism.
Scheme 2: Reaction patterns of alkyne metathesis.
Scheme 3: Typical examples from traditional catalyst systems.
Scheme 4: Ligand synthesis and catalyst design.
Scheme 5: Catalysts synthesis using high- and low-oxidation-state routes (for 6a, X = Li or K; for 6b, X = K)....
Figure 1: Alkylidyne complexes 9 and 10.
Scheme 6: Design strategy of Fürstner’s new system.
Scheme 7: Synthetic routes of Fürstner’s new catalysts.
Scheme 8: Lewis acid addition of 26 and 28.
Scheme 9: Preparation of the silanolate–alkylidyne tungsten complex 39.
Molecular recognition of organic ammonium ions in solution using synthetic receptors
- Andreas Späth and
- Burkhard König
Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32
Graphical Abstract
Figure 1: Biologically important amines and quaternary ammonium salts: histamine (1), dopamine (2) and acetyl...
Figure 2: Crown ether 18-crown-6.
Figure 3: Conformations of 18-crown-6 (4) in solvents of different polarity.
Figure 4: Binding topologies of the ammonium ion depending on the crown ring size.
Figure 5: A “pseudorotaxane” structure consisting of 24-crown-8 and a secondary ammonium ion (5); R = Ph.
Figure 6: Typical examples of azacrown ethers, cryptands and related aza macrocycles.
Figure 7: Binding of ammonium to azacrown ethers and cryptands [111-113].
Figure 8: A 19-crown-6-ether with decalino blocking groups (11) and a thiazole-dibenzo-18-crown-6-ether (12).
Figure 9: 1,3-Bis(6-oxopyridazin-1-yl)propane derivatives 13 and 14 by Campayo et al.
Figure 10: Fluorescent azacrown-PET-sensors based on coumarin.
Figure 11: Two different pyridino-cryptands (17 and 18) compared to a pyridino-crown (19); chiral ammonium ion...
Figure 12: Pyridino-18-crown-6 ligand (21), a similar acridino-18-crown-6 ligand (22) and a structurally relat...
Figure 13: Ciral pyridine-azacrown ether receptors 24.
Figure 14: Chiral 15-crown-5 receptors 26 and an analogue 18-crown-6 ligand 27 derived from amino alcohols.
Figure 15: C2-symmetric chiral 18-crown-6 amino alcohol derivatives 28 and related macrocycles.
Figure 16: Macrocycles with diamide-diester groups (30).
Figure 17: C2-symmetric chiral aza-18-crown-6 ethers (31) with phenethylamine residues.
Figure 18: Chiral C-pivot p-methoxy-phenoxy-lariat ethers.
Figure 19: Chiral lariat crown ether 34.
Figure 20: Sucrose-based chiral crown ether receptors 36.
Figure 21: Permethylated fructooligosaccharide 37 showing induced-fit chiral recognition.
Figure 22: Biphenanthryl-18-crown-6 derivative 38.
Figure 23: Chiral lariat crown ethers derived from binol by Fuji et al.
Figure 24: Chiral phenolic crown ether 41 with “aryl chiral barriers” and guest amines.
Figure 25: Chiral bis-crown receptor 43 with a meso-ternaphthalene backbone.
Figure 26: Chromogenic pH-dependent bis-crown chemosensor 44 for diamines.
Figure 27: Triamine guests for binding to receptor 44.
Figure 28: Chiral bis-crown phenolphthalein chemosensors 46.
Figure 29: Crown ether amino acid 47.
Figure 30: Luminescent receptor 48 for bis-alkylammonium guests.
Figure 31: Luminescent CEAA (49a), a bis-CEAA receptor for amino acids (49b) and the structure of lysine bindi...
Figure 32: Luminescent CEAA tripeptide for binding small peptides.
Figure 33: Bis crown ether 51a self assembles co-operatively with C60-ammonium ion 51b.
Figure 34: Triptycene-based macrotricyclic dibenzo-[24]-crown-8 ether host 52 and guests.
Figure 35: Copper imido diacetic acid azacrown receptor 53a and the suggested His-Lys binding motif; a copper ...
Figure 36: Urea (54) and thiourea (55) benzo crown receptor for transport and extraction of amino acids.
Figure 37: Crown pyryliums ion receptors 56 for amino acids.
Figure 38: Ditopic sulfonamide bridged crown ether receptor 57.
Figure 39: Luminescent peptide receptor 58.
Figure 40: Luminescent receptor 59 for the detection of D-glucosamine hydrochloride in water/ethanol and lumin...
Figure 41: Guanidinium azacrown receptor 61 for simple amino acids and ditopic receptor 62 with crown ether an...
Figure 42: Chiral bicyclic guanidinium azacrown receptor 63 and similar receptor 64 for the enantioselective t...
Figure 43: Receptors for zwitterionic species based on luminescent CEAAs.
Figure 44: 1,10-Azacrown ethers with sugar podand arms and the anticancer agent busulfan.
Figure 45: Benzo-18-crown-6 modified β-cyclodextrin 69 and β-cyclodextrin functionalized with diaza-18-crown-6...
Figure 46: Receptors for colorimetric detection of primary and secondary ammonium ions.
Figure 47: Porphyrine-crown-receptors 72.
Figure 48: Porphyrin-crown ether conjugate 73 and fullerene-ammonium ion guest 74.
Figure 49: Calix[4]arene (75a), homooxocalix[4]arene (75b) and resorcin[4]arene (75c) compared (R = H, alkyl c...
Figure 50: Calix[4]arene and ammonium ion guest (R = H, alkyl, OAcyl etc.), possible binding sites; A: co-ordi...
Figure 51: Typical guests for studies with calixarenes and related molecules.
Figure 52: Lower rim modified p-tert-butylcalix[5]arenes 82.
Figure 53: The first example of a water soluble calixarene.
Figure 54: Sulfonated water soluble calix[n]arenes that bind ammonium ions.
Figure 55: Displacement assay for acetylcholine (3) with a sulfonato-calix[6]arene (84b).
Figure 56: Amino acid inclusion in p-sulfonatocalix[4]arene (84a).
Figure 57: Calixarene receptor family 86 with upper and lower rim functionalization.
Figure 58: Calix[6]arenes 87 with one carboxylic acid functionality.
Figure 59: Sulfonated calix[n]arenes with mono-substitution at the lower rim systematically studied on their r...
Figure 60: Cyclotetrachromotropylene host (91) and its binding to lysine (81c).
Figure 61: Calixarenes 92 and 93 with phosphonic acids groups.
Figure 62: Calix[4]arene tetraphosphonic acid (94a) and a double bridged analogue (94b).
Figure 63: Calix[4]arene tetraphosphonic acid ester (92c) for surface recognition experiments.
Figure 64: Calixarene receptors 95 with α-aminophosphonate groups.
Figure 65: A bridged homocalix[3]arene 95 and a distally bridged homocalix[4]crown 96.
Figure 66: Homocalix[3]arene ammonium ion receptor 97a and the Reichardt’s dye (97b) for colorimetric assays.
Figure 67: Chromogenic diazo-bridged calix[4]arene 98.
Figure 68: Calixarene receptor 99 by Huang et al.
Figure 69: Calixarenes 100 reported by Parisi et al.
Figure 70: Guest molecules for inclusion in calixarenes 100: DAP × 2 HCl (101a), APA (101b) and Lys-OMe × 2 HC...
Figure 71: Different N-linked peptido-calixarenes open and with glycol chain bridges.
Figure 72: (S)-1,1′-Bi-2-naphthol calixarene derivative 104 published by Kubo et al.
Figure 73: A chiral ammonium-ion receptor 105 based on the calix[4]arene skeleton.
Figure 74: R-/S-phenylalaninol functionalized calix[6]arenes 106a and 106b.
Figure 75: Capped homocalix[3]arene ammonium ion receptor 107.
Figure 76: Two C3 symmetric capped calix[6]arenes 108 and 109.
Figure 77: Phosphorous-containing rigidified calix[6]arene 110.
Figure 78: Calix[6]azacryptand 111.
Figure 79: Further substituted calix[6]azacryptands 112.
Figure 80: Resorcin[4]arene (75c) and the cavitands (113).
Figure 81: Tetrasulfonatomethylcalix[4]resorcinarene (114).
Figure 82: Resorcin[4]arenes (115a/b) and pyrogallo[4]arenes (115c, 116).
Figure 83: Displacement assay for acetylcholine (3) with tetracyanoresorcin[4]arene (117).
Figure 84: Tetramethoxy resorcinarene mono-crown-5 (118).
Figure 85: Components of a resorcinarene based displacement assay for ammonium ions.
Figure 86: Chiral basket resorcin[4]arenas 121.
Figure 87: Resorcinarenes with deeper cavitand structure (122).
Figure 88: Resorcinarene with partially open deeper cavitand structure (123).
Figure 89: Water-stabilized deep cavitands with partially structure (124, 125).
Figure 90: Charged cavitands 126 for tetralkylammonium ions.
Figure 91: Ditopic calix[4]arene receptor 127 capped with glycol chains.
Figure 92: A calix[5]arene dimer for diammonium salt recognition.
Figure 93: Calixarene parts 92c and 129 for the formation molecular capsules.
Figure 94: Encapsulation of a quaternary ammonium cation by two resorcin[4]arene molecules (NMe4+@[75c]2 × Cl−...
Figure 95: Encapsulation of a quaternary ammonium cation by six resorcin[4]arene molecules (NMe3D+@[130]6 × Cl−...
Figure 96: Structure and schematic of cucurbit[6]uril (CB[6], 131a).
Figure 97: Cyclohexanocucurbit[6]uril (CB′[6], 132) and the guest molecule spermine (133).
Figure 98: α,α,δ,δ-Tetramethylcucurbit[6]uril (134).
Figure 99: Structure of the cucurbituril-phthalhydrazide analogue 135.
Figure 100: Organic cavities for the displacement assay for amine differentiation.
Figure 101: Displacement assay methodology for diammonium- and related guests involving cucurbiturils and some ...
Figure 102: Nor-seco-Cucurbituril (±)-bis-ns-CB[6] (140) and guest molecules.
Figure 103: The cucurbit[6]uril based complexes 141 for chiral discrimination.
Figure 104: Cucurbit[7]uril (131c) and its ferrocene guests (142) opposed.
Figure 105: Cucurbit[7]uril (131c) guest inclusion and representative guests.
Figure 106: Cucurbit[7]uril (131c) binding to succinylcholine (145) and different bis-ammonium and bis-phosphon...
Figure 107: Paraquat-cucurbit[8]uril complex 149.
Figure 108: Gluconuril-based ammonium receptors 150.
Figure 109: Examples of clefts (151a), tweezers (151b, 151c, 151d) and clips (151e).
Figure 110: Kemp’s triacid (152a), on example of Rebek’s receptors (152b) and guests.
Figure 111: Amino acid receptor (154) by Rebek et al.
Figure 112: Hexagonal lattice designed hosts by Bell et al.
Figure 113: Bell’s amidinium receptor (156) and the amidinium ion (157).
Figure 114: Aromatic phosphonic acids.
Figure 115: Xylene phosphonates 159 and 160a/b for recognition of amines and amino alcohols.
Figure 116: Bisphosphonate recognition motif 161 for a colorimetric assay with alizarin complexone (163) for ca...
Figure 117: Bisphosphonate/phosphate clip 164 and bisphosphonate cleft 165.
Figure 118: N-Methylpyrazine 166a, N-methylnicotinamide iodide (166b) and NAD+ (166c).
Figure 119: Bisphosphate cavitands.
Figure 120: Bisphosphonate 167 of Schrader and Finocchiaro.
Figure 121: Tweezer 168 for noradrenaline (80b).
Figure 122: Different tripods and heparin (170).
Figure 123: Squaramide based receptors 172.
Figure 124: Cage like NH4+ receptor 173 of Kim et al.
Figure 125: Ammonium receptors 174 of Chin et al.
Figure 126: 2-Oxazolin-based ammonium receptors 175a–d and 176 by Ahn et al.
Figure 127: Racemic guest molecules 177.
Figure 128: Tripods based on a imidazole containing macrocycle (178) and the guest molecules employed in the st...
Figure 129: Ammonium ion receptor 180.
Figure 130: Tetraoxa[3.3.3.3]paracyclophanes 181 and a cyclophanic tetraester (182).
Figure 131: Peptidic bridged paraquat-cyclophane.
Figure 132: Shape-selective noradrenaline host.
Figure 133: Receptor 185 for binding of noradrenaline on surface layers from Schrader et al.
Figure 134: Tetraphosphonate receptor for binding of noradrenaline.
Figure 135: Tetraphosphonate 187 of Schrader and Finocchiaro.
Figure 136: Zinc-Porphyrin ammonium-ion receptors 188 and 189 of Mizutani et al.
Figure 137: Zinc porphyrin receptor 190.
Figure 138: Zinc porphyrin receptors 191 capable of amino acid binding.
Figure 139: Zinc-porphyrins with amino acid side chains for stereoinduction.
Figure 140: Bis-zinc-bis-porphyrin based on Tröger’s base 193.
Figure 141: BINAP-zinc-prophyrin derivative 194 and it’s guests.
Figure 142: Bisaryl-linked-zinc-porphyrin receptors.
Figure 143: Bis-zinc-porphyrin 199 for diamine recognition and guests.
Figure 144: Bis-zinc-porphyrin crown ether 201.
Figure 145: Bis-zinc-porphyrin 202 for stereodiscrimination (L = large substituent; S = small substituent).
Figure 146: Bis-zinc-porphyrin[3]rotaxane and its copper complex and guests.
Figure 147: Dien-bipyridyl ligand 206 for co-ordination of two metal atoms.
Figure 148: The ligand and corresponding tetradentate co-complex 207 serving as enantioselective receptor for a...
Figure 149: Bis(oxazoline)–copper(II) complex 208 for the recognition of amino acids in aqueous solution.
Figure 150: Zinc-salen-complexes 209 for the recognition tertiary amines.
Figure 151: Bis(oxazoline)–copper(II) 211 for the recognition of amino acids in aqueous solution.
Figure 152: Zn(II)-complex of a C2 terpyridine crown ether.
Figure 153: Displacement assay and receptor for aspartate over glutamate.
Figure 154: Chiral complex 214 for a colorimetric displacement assay for amino acids.
Figure 155: Metal complex receptor 215 with tripeptide side arms.
Figure 156: A sandwich complex 216 and its displaceable dye 217.
Figure 157: Lanthanide complexes 218–220 for amino acid recognition.
Figure 158: Nonactin (221), valinomycin (222) and vancomycin (223).
Figure 159: Monesin (224a) and a chiral analogue for enantiodiscrimination of ammonium guests (224b).
Figure 160: Chiral podands (226) compared to pentaglyme-dimethylether (225) and 18-crown-6 (4).
Figure 161: Lasalocid A (228).
Figure 162: Lasalocid derivatives (230) of Sessler et al.
Figure 163: The Coporphyrin I tetraanion (231).
Figure 164: Linear and cyclic peptides for ammonium ion recognition.
Figure 165: Cyclic and bicyclic depsipeptides for ammonium ion recognition.
Figure 166: α-Cyclodextrin (136a) and novocaine (236).
Figure 167: Helical diol receptor 237 by Reetz and Sostmann.
Figure 168: Ammonium binding spherand by Cram et al. (238a) and the cyclic[6]metaphenylacetylene 238b in compar...
Figure 169: Receptor for peptide backbone and ammonium binding (239).
Figure 170: Anion sensor principle with 3-hydroxy-2-naphthanilide of Jiang et al.
Figure 171: 7-bromo-3-hydroxy-N-(2-hydroxyphenyl)naphthalene 2-carboxamide (241) and its amine binding.
Figure 172: Naturally occurring catechins with affinity to quaternary ammonium ions.
Figure 173: Spiropyran (244) and merocyanine form (244a) of the amino acid receptors of Fuji et al.
Figure 174: Coumarin aldehyde (245) and its iminium species with amino acid bound (245a) by Glass et al.
Figure 175: Coumarin aldehyde appended with boronic acid.
Figure 176: Quinolone aldehyde dimers by Glass et al.
Figure 177: Chromogenic ammonium ion receptors with trifluoroacetophenone recognition motifs.
Figure 178: Chromogenic ammonium ion receptor with trifluoroacetophenone recognition motif bound on different m...
Recent progress on the total synthesis of acetogenins from Annonaceae
- Nianguang Li,
- Zhihao Shi,
- Yuping Tang,
- Jianwei Chen and
- Xiang Li
Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48
- two different procedures afforded isomeric epoxides 17 and 18, respectively. Coupling between the lithium salt of 13 and 17 (or 18) followed by hydrogenation, oxidation and deprotection afforded (8′S)- or (8′R)-8a. Comparison of the mp, [α]D, IR and NMR data of both synthetic materials with those
Graphical Abstract
Scheme 1: Total synthesis of longifolicin by Marshall’s group.
Scheme 2: Total synthesis of corossoline by Tanaka’s group.
Scheme 3: Total synthesis of corossoline by Wu’s group.
Scheme 4: Total synthesis of pseudo-annonacin A by Hanessian’s group.
Scheme 5: Total synthesis of tonkinecin by Wu’s group.
Scheme 6: Total synthesis of gigantetrocin A by Shi’s group.
Scheme 7: Total synthesis of annonacin by Wu’s group.
Scheme 8: Total synthesis of solamin by Kitahara’s group.
Scheme 9: Total synthesis of solamin by Mioskowski’s group.
Scheme 10: Total synthesis of cis-solamin by Makabe’s group.
Scheme 11: Total synthesis of cis-solamin by Brown’s group.
Scheme 12: The formal synthesis of (+)-cis-solamin by Donohoe’s group.
Scheme 13: Total synthesis of cis-solamin by Stark’s group.
Scheme 14: Total synthesis of mosin B by Tanaka’s group.
Scheme 15: Total synthesis of longicin by Hanessian’s group.
Scheme 16: Total synthesis of murisolin and 16,19-cis-murisolin by Tanaka’s group.
Scheme 17: Synthesis of a stereoisomer library of (+)-murisolin by Curran’s group.
Scheme 18: Total synthesis of murisolin by Makabe’s group.
Scheme 19: Total synthesis of reticulatain-1 by Makabe’s group.
Scheme 20: Total synthesis of muricatetrocin C by Ley’s group.
Scheme 21: Total synthesis of (4R,12S,15S,16S,19R,20R,34S)-muricatetrocin (146) and (4R,12R,15S,16S,19R,20R,34S...
Scheme 22: Total synthesis of parviflorin by Hoye’s group.
Scheme 23: Total synthesis of parviflorin by Trost’s group.
Scheme 24: Total synthesis of trilobacin by Sinha’s group.
Scheme 25: Total synthesis of 15-epi-annonin I 181b by Scharf’s group.
Scheme 26: Total synthesis of squamocin A and squamocin D by Scharf’s group.
Scheme 27: Total synthesis of asiminocin by Marshall’s group.
Scheme 28: Total synthesis of asiminecin by Marshall’s group.
Scheme 29: Total synthesis of (+)-(30S)-bullanin by Marshall’s group.
Scheme 30: Total synthesis of uvaricin by the group of Sinha and Keinan.
Scheme 31: Formal synthesis of uvaricin by Burke’s group.
Scheme 32: Total synthesis of trilobin by Marshall’s group.
Scheme 33: Total synthesis of trilobin by the group of Sinha and Keinan.
Scheme 34: Total synthesis of asimilobin by the group of Wang and Shi.
Scheme 35: Total synthesis of squamotacin by the group of Sinha and Keinan.
Scheme 36: Total synthesis of asimicin by Marshall’s group.
Scheme 37: Total synthesis of asimicin by the group of Sinha and Keinan.
Scheme 38: Total synthesis of asimicin by Roush’s group.
Scheme 39: Total synthesis of asimicin by Marshall’s group.
Scheme 40: Total synthesis of 10-hydroxyasimicin by Ley’s group.
Scheme 41: Total synthesis of asimin by Marshall’s group.
Scheme 42: Total synthesis of bullatacin by the group of Sinha and Keinan.
Scheme 43: Total synthesis of bullatacin by Roush’s group.
Scheme 44: Total synthesis of bullatacin by Pagenkopf’s group.
Scheme 45: Total synthesis of rollidecins C and D by the group of Sinha and Keinan.
Scheme 46: Total synthesis of 30(S)-hydroxybullatacin by Marshall’s group.
Scheme 47: Total synthesis of uvarigrandin A and 5(R)-uvarigrandin A by Marshall’s group.
Scheme 48: Total synthesis of membranacin by Brown’s group.
Scheme 49: Total synthesis of membranacin by Lee’s group.
Scheme 50: Total synthesis of rolliniastatin 1 and rollimembrin by Lee’s group.
Scheme 51: Total synthesis of longimicin D by the group of Maezaki and Tanaka.
Scheme 52: Total synthesis of the structure proposed for mucoxin by Borhan’s group.
Scheme 53: Modular synthesis of adjacent bis-THF annonaceous acetogenins by Marshall’s group.
Scheme 54: Total synthesis of 4-deoxygigantecin by Tanaka’s group.
Scheme 55: Total synthesis of squamostatins D by Marshall’s group.
Scheme 56: Total synthesis of gigantecin by Crimmins’s group.
Scheme 57: Total synthesis of gigantecin by Hoye’s group.
Scheme 58: Total synthesis of cis-sylvaticin by Donohoe’s group.
Scheme 59: Total synthesis of 17(S),18(S)-goniocin by Sinha’s group.
Scheme 60: Total synthesis of goniocin and cyclogoniodenin T by the group of Sinha and Keinan.
Scheme 61: Total synthesis of jimenezin by Takahashi’s group.
Scheme 62: Total synthesis of jimenezin by Lee’s group.
Scheme 63: Total synthesis of jimenezin by Hoffmann’s group.
Scheme 64: Total synthesis of muconin by Jacobsen’s group.
Scheme 65: Total synthesis of (+)-muconin by Kitahara’s group.
Scheme 66: Total synthesis of muconin by Takahashi’s group.
Scheme 67: Total synthesis of muconin by the group of Yoshimitsu and Nagaoka.
Scheme 68: Total synthesis of mucocin by the group of Sinha and Keinan.
Scheme 69: Total synthesis of mucocin by Takahashi’s group.
Scheme 70: Total synthesis of (−)-mucocin by Koert’s group.
Scheme 71: Total synthesis of mucocin by the group of Takahashi and Nakata.
Scheme 72: Total synthesis of mucocin by Evans’s group.
Scheme 73: Total synthesis of mucocin by Mootoo’s group.
Scheme 74: Total synthesis of (−)-mucocin by Crimmins’s group.
Scheme 75: Total synthesis of pyranicin by the group of Takahashi and Nakata.
Scheme 76: Total synthesis of pyranicin by Rein’s group.
Scheme 77: Total synthesis of proposed pyragonicin by the group of Takahashi and Nakata.
Scheme 78: Total synthesis of pyragonicin by Rein’s group.
Scheme 79: Total synthesis of pyragonicin by Takahashi’s group.
Scheme 80: Total synthesis of squamostanal A by Figadère’s group.
Scheme 81: Total synthesis of diepomuricanin by Tanaka’s group.
Scheme 82: Total synthesis of (−)-muricatacin [(R,R)-373a] and its enantiomer (+)-muricatacin [(S,S)-373b] by ...
Scheme 83: Total synthesis of epi-muricatacin (+)-(S,R)-373c and (−)-(R,S)-373d by Scharf’s group.
Scheme 84: Total synthesis of (−)-muricatacin 373a and 5-epi-(−)-muricatacin 373d by Uang’s group.
Scheme 85: Total synthesis of four stereoisomers of muricatacin by Yoon’s group.
Scheme 86: Total synthesis of (+)-muricatacin by Figadère’s group.
Scheme 87: Total synthesis of (+)-epi-muricatacin and (−)-muricatacin by Couladouros’s group.
Scheme 88: Total synthesis of muricatacin by Trost’s group.
Scheme 89: Total synthesis of (−)-(4R,5R)-muricatacin by Heck and Mioskowski’s group.
Scheme 90: Total synthesis of muricatacin (−)-373a by the group of Carda and Marco.
Scheme 91: Total synthesis of (−)- and (+)-muricatacin by Popsavin’s group.
Scheme 92: Total synthesis of (−)-muricatacin by the group of Bernard and Piras.
Scheme 93: Total synthesis of (−)-muricatacin by the group of Yoshimitsu and Nagaoka.
Scheme 94: Total synthesis of (−)-muricatacin by Quinn’s group.
Scheme 95: Total synthesis of montecristin by Brückner’s group.
Scheme 96: Total synthesis of (−)-acaterin by the group of Franck and Figadère.
Scheme 97: Total synthesis of (−)-acaterin by Singh’s group.
Scheme 98: Total synthesis of (−)-acaterin by Kumar’s group.
Scheme 99: Total synthesis of rollicosin by Quinn’s group.
Scheme 100: Total synthesis of Rollicosin by Makabe’s group.
Scheme 101: Total synthesis of squamostolide by Makabe’s group.
Scheme 102: Total synthesis of tonkinelin by Makabe’s group.
Development of potential manufacturing routes for substituted thiophenes – Preparation of halogenated 2-thiophenecarboxylic acid derivatives as building blocks for a new family of 2,6-dihaloaryl 1,2,4-triazole insecticides
- John W. Hull Jr.,
- Duane R. Romer,
- David E. Podhorez,
- Mezzie L. Ash and
- Christine H. Brady
Beilstein J. Org. Chem. 2007, 3, No. 23, doi:10.1186/1860-5397-3-23
- of lithium salt. However, the lithiation route requires sub-zero cooling, and n-butyllithium has a significantly higher cost per mole than magnesium metal. The requirement of a -60°C reaction temperature for lithium/chlorine exchange will require a significant capital expenditure in refrigeration
Graphical Abstract
Figure 1: Thiophene structures 1, 2, and 3.
Figure 2: XR-693 and XR-906.
Scheme 1: Synthesis and Reactivity of 2,4,5-Tribromo-3-methylthiophene. Initial Bromination Approaches.
Scheme 2: Routes to 4-Bromo-3-methyl-2-thiopheneacid Chloride, 1, From 3-Methylthiophene, 4. (a) NBS/AcOH, 64...
Scheme 3: Vapor Phase Chlorination of 2-Thiophenecarbonitrile.
Scheme 4: Synthesis of 3,4,5-Trichloro-2-thiopheneacid Chloride, 2. (a) 1. n-BuLi/MTBE, -60°C, 2. CO2; or 1. ...
Scheme 5: Metal-Halogen Exchange in THF Solvent.
