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Search for "vinyl halide" in Full Text gives 8 result(s) in Beilstein Journal of Organic Chemistry.
Total synthesis of grayanane natural products
- Nicolas Fay,
- Rémi Blieck,
- Cyrille Kouklovsky and
- Aurélien de la Torre
Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181
- diastereoselectivity in 58% on a 3 g scale. Subsequently, vinyl halide 48 was converted to diene 50 by Suzuki coupling with potassium vinyltrifluoroborate (49) in 90% yield (Scheme 8). The C7–C8 bond formation from a bridgehead carbocation was a real challenge to close the 7-membered ring. To achieve this, the
Graphical Abstract
Figure 1: General structure of grayanane natural products.
Scheme 1: Grayanane biosynthesis.
Scheme 2: Matsumoto’s relay approach.
Scheme 3: Shirahama’s total synthesis of (–)-grayanotoxin III.
Scheme 4: Newhouse’s syntheses of fragments 25 and 29.
Scheme 5: Newhouse’s total synthesis of principinol D.
Scheme 6: Ding’s total synthesis of rhodomolleins XX and XXII.
Scheme 7: First key step of Luo’s strategy.
Scheme 8: Luo’s total synthesis of grayanotoxin III.
Scheme 9: Synthesis of principinol E and rhodomollein XX.
Scheme 10: William’s synthetic effort towards pierisformaside C.
Scheme 11: Hong’s synthetic effort towards rhodojaponin III.
Scheme 12: Recent strategies for grayanane synthesis.
Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions
- Surendran Amrutha,
- Sankaran Radhika and
- Gopinathan Anilkumar
Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31
- reaction between an aryl/vinyl halide (Cl, Br, I, OTf) and a terminal alkyne in the presence of a Cu(I) co-catalyst under basic conditions to form a Csp2–Csp bond generating an arylalkyne is known as the Sonogashira (Sonogashira–Hagihara) coupling [1] and has become an important C–C bond-forming reaction
- iodides showed good to excellent yields when coupled with phenylacetylene. The proposed mechanism is similar to the standard palladium-catalyzed Sonogashira reaction with the steps involving oxidative addition of the aryl/vinyl halide followed by transmetallation, and reductive elimination. The mechanism
- (Scheme 15). The precatalyst FeCl2 is activated under the reaction conditions which is denoted as complex A. The reaction begins with the oxidative addition of aryl/vinyl halide forming complex B. Iron acetylide on reaction with this complex in a transmetallation step yields complex C. The resulting
Graphical Abstract
Scheme 1: One pot Sonogashira coupling of aryl iodides with arylynols in the presence of iron(III) chloride h...
Scheme 2: The iron-catalyzed Sonogashira coupling of aryl iodides with terminal acetylenes in water under aer...
Scheme 3: Sonogashira coupling of aryl halides and phenylacetylene in the presence of iron nanoparticles.
Scheme 4: Sonogashira coupling catalyzed by a silica-supported heterogeneous Fe(III) catalyst.
Scheme 5: Suggested catalytic cycle for the Sonogashira coupling using a silica-supported heterogeneous Fe(II...
Scheme 6: Chemoselective iron-catalyzed cross coupling of 4-bromo-1-cyclohexen-1-yltrifluromethane sulfonate ...
Scheme 7: Fe-catalyzed Sonogashira coupling between terminal alkynes and aryl iodides.
Scheme 8: Iron-catalyzed domino Sonogashira coupling and hydroalkoxylation.
Scheme 9: Sonogashira coupling of aryl halides and phenylacetylene in the presence of Fe(III) acetylacetonate...
Scheme 10: Sonogashira coupling of aryl iodides and alkynes with Fe(acac)3/2,2-bipyridine catalyst.
Scheme 11: Sonogashira cross-coupling of terminal alkynes with aryl iodides in the presence of Fe powder/ PPh3...
Scheme 12: α-Fe2O3 nanoparticles-catalyzed coupling of phenylacetylene with aryl iodides.
Scheme 13: Sonogashira cross-coupling reaction between phenylacetylene and 4-substituted iodobenzenes catalyze...
Scheme 14: One-pot synthesis of 2-arylbenzo[b]furans via tandem Sonogashira coupling–cyclization protocol.
Scheme 15: Suggested mechanism of the Fe(III) catalyzed coupling of o-iodophenol with acetylene derivatives.
Scheme 16: Fe3O4@SiO2/Schiff base/Fe(II)-catalyzed Sonogashira–Hagihara coupling reaction.
Scheme 17: Sonogashira coupling using the Fe(II)(bdmd) catalyst in DMF/1,4-dioxane.
Scheme 18: Synthesis of 7-azaindoles using Fe(acac)3 as catalyst.
Scheme 19: Plausible mechanistic pathway for the synthesis of 7-azaindoles.
Scheme 20: Synthesis of Co@imine-POP catalyst.
Scheme 21: Sonogashira coupling of various arylhalides and phenylacetylene in the presence of Co@imine-POP cat...
Scheme 22: Sonogashira coupling of aryl halides and phenylacetylene using Co-DMM@MNPs/chitosan.
Scheme 23: Sonogashira cross-coupling of aryl halides with terminal acetylenes in the presence of Co-NHC@MWCNT...
Scheme 24: Sonogashira cross-coupling of aryl halides with terminal acetylenes in the presence of Co nanoparti...
Scheme 25: Sonogashira coupling reaction of aryl halides with phenylacetylene in the presence of Co nanopartic...
Scheme 26: PdCoNPs-3DG nanocomposite-catalyzed Sonogashira cross coupling of aryl halide and terminal alkynes.
Scheme 27: Sonogashira cross-coupling of aryl halides and phenylacetylene in the presence of graphene-supporte...
Scheme 28: Sonogashira cross-coupling with Pd/Co ANP-PPI-graphene.
Scheme 29: Pd-Co-1(H)-catalyzed Sonogashira coupling reaction.
Scheme 30: The coupling of aryl halides with terminal alkynes using cobalt hollow nanospheres as catalyst.
Scheme 31: A plausible mechanism for the cobalt-catalyzed Sonogashira coupling reaction.
Scheme 32: Sonogashira cross-coupling reaction of arylhalides with phenylacetylene catalyzed by Fe3O4@PEG/Cu-C...
Scheme 33: Plausible mechanism of Sonogashira cross-coupling reaction catalyzed by Fe3O4@PEG/Cu-Co.
Scheme 34: Sonogashira coupling reaction of para-substituted bromobenzenes with phenylacetylene in the presenc...
Scheme 35: Possible mechanism for the visible light-assisted cobalt complex-catalyzed Sonogashira coupling. (R...
Scheme 36: Sonogashira cross-coupling of aryl halides and phenylacetylene using cobalt as additive.
Scheme 37: Plausible mechanism of Sonogashira cross-coupling reaction over [LaPd*]. (Reproduced with permissio...
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
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.
A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE
- Tue Heesgaard Jepsen,
- Emil Glibstrup,
- François Crestey,
- Anders A. Jensen and
- Jesper Langgaard Kristensen
Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98
- pharmacological evaluations support the notion that the key pharmacophores of DHβE are located in the A and B rings. Keywords: DhβE; Mizoroki–Heck cross-coupling reaction; 6π-electrocyclization; [6,6]-bicyclic lactone; vinyl halide; Introduction The neuronal nicotinic acetylcholine receptors (nAChRs) have been
- the C ring by an intramolecular Mizoroki–Heck cross-coupling reaction from a Z-configured olefin which would be crucial to the stereochemical outcome of the Heck cyclization event. We envisioned a Z-stereoselective synthesis of a vinyl halide [17] which should secure the desired E-stereochemistry for
Graphical Abstract
Figure 1: DHβE and related structures. The Ki values of the compounds at the rat α4β2 nAChR subtype determine...
Scheme 1: First strategy towards the CD fragment (Ts-strategy). i) TsCl, TEA, DCM, 0 °C. ii) NaH, DMF, 0 °C, ...
Scheme 2: First strategy towards the CD fragment (Cbz-strategy). i) R-Cl, TEA, CH2Cl2, 0 °C. ii) NaH, DMF, 0 ...
Scheme 3: Second strategy towards the CD fragment. i) 4-Bromobut-1-ene, K2CO3, acetone, 70 °C. ii) n-BuLi, TH...
Figure 2: The binding affinities of compounds 9 and 26 at the rat α4β2 nAChR. a) The AB fragment was evaluate...
Studies on the synthesis of peptides containing dehydrovaline and dehydroisoleucine based on copper-mediated enamide formation
- Franziska Gille and
- Andreas Kirschning
Beilstein J. Org. Chem. 2016, 12, 564–570, doi:10.3762/bjoc.12.55
- conjugated alkene. Principally, enamides can also be prepared by the copper-mediated C–N coupling between a vinyl halide 6 and an amide 5 as reported by Ogawa and co-workers in 1991 [6]. Later, the group of Porco showed that copper(I) thiophencarboxylate is a suitable catalyst to promote this reaction in the
Graphical Abstract
Scheme 1: Selected examples of oligopeptides bearing dehydroamino acid moieties: myxovalargin (1), argyrin A (...
Scheme 2: The Buchwald cross-coupling reaction in the preparation of peptides containing dehydroamino acids 4....
Scheme 3: Syntheses of vinyl iodides 10 and 11.
Scheme 4: Preparation of vinyl iodides 24–29 (Cbz = benzyloxycarbonyl, Alloc = allyloxycarbonyl, Boc = tert-b...
Scheme 5: Copper-mediated C–N cross-coupling of dehydropeptides 31–33, 36, 37, and 39–41.
Scheme 6: C–N coupling reaction between amide 43 and vinyl iodide 42; formation of dehydroisoleucine containi...
Preparation of phosphines through C–P bond formation
- Iris Wauters,
- Wouter Debrouwer and
- Christian V. Stevens
Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106
- coupling of several vinyl bromides 75b and chlorides with 25d (Table 10). These reactions proceeded without the addition of zinc [167]. Copper: The group of Buchwald has reported one example of a copper catalyst to accomplish the phosphination of the vinyl halide 94 (Scheme 26) [168]. The protocol uses CuI
Graphical Abstract
Scheme 1: Synthesis of P-stereogenic phosphines 5 using menthylphosphinite borane diastereomers 2.
Scheme 2: Enantioselective synthesis of chiral phosphines 10 with ephedrine as a chiral auxiliary.
Scheme 3: Chlorophosphine boranes 11a as P-chirogenic electrophilic building blocks.
Scheme 4: Monoalkylation of phenylphosphine borane 15 with methyl iodide in the presence of Cinchona alkaloid...
Scheme 5: Preparation of tetraphosphine borane 19.
Scheme 6: Using chiral chlorophosphine-boranes 11b as phosphide borane 20 precursors.
Scheme 7: Nickel-catalyzed cross-coupling (dppe = 1,2-bis(diphenylphosphino)ethane).
Scheme 8: Pd-catalyzed cross-coupling reaction with organophosphorus stannanes 30.
Scheme 9: Copper iodide catalyzed carbon–phosphorus bond formation.
Scheme 10: Thermodynamic kinetic resolution as the origin of enantioselectivity in metal-catalyzed asymmetric ...
Scheme 11: Ru-catalyzed asymmetric phosphination of benzyl and alkyl chlorides 35 with HPPhMe (36a, PHOX = pho...
Scheme 12: Pt-catalyzed asymmetric alkylation of secondary phosphines 36b.
Scheme 13: Different adducts 43 can result from hydrophosphination.
Scheme 14: Pt-catalyzed asymmetric hydrophosphination.
Scheme 15: Intramolecular hydrophosphination of phosphinoalkene 47.
Scheme 16: Organocatalytic asymmetric hydrophosphination of α,β-unsaturated aldehydes 59.
Scheme 17: Preparation of phosphines using zinc organometallics.
Scheme 18: Preparation of alkenylphosphines 71a from alkenylzirconocenes 69 (dtc = N,N-diethyldithiocarbamate,...
Scheme 19: SNAr with P-chiral alkylmethylphosphine boranes 13c.
Scheme 20: Synthesis of QuinoxP 74 (TMEDA = tetramethylethylenediamine).
Scheme 21: Pd-Mediated couplings of a vinyl triflate 76 with diphenylphosphine borane 13e.
Figure 1: Menthone (83) and camphor (84) derived chiral phosphines.
Scheme 22: Palladium-catalyzed cross-coupling reaction of vinyl tosylates 85 and 87 with diphenylphosphine bor...
Scheme 23: Attempt for the enantioselective palladium-catalyzed C–P cross-coupling reaction between an alkenyl...
Scheme 24: Enol phosphates 88 as vinylic coupling partners in the palladium-catalyzed C–P cross-coupling react...
Scheme 25: Nickel-catalyzed cross-coupling in the presence of zinc (dppe = 1,2-bis(diphenylphosphino)ethane).
Scheme 26: Copper-catalyzed coupling of secondary phosphines with vinyl halide 94.
Scheme 27: Palladium-catalyzed cross-coupling of aryl iodides 97 with organoheteroatom stannanes 30.
Scheme 28: Synthesis of optically active phosphine boranes 100 by cross-coupling with a chiral phosphine boran...
Scheme 29: Palladium-catalyzed P–C cross-coupling reactions between primary or secondary phosphines and functi...
Scheme 30: Enantioselective synthesis of a P-chirogenic phosphine 108.
Scheme 31: Enantioselective arylation of silylphosphine 110 ((R,R)-Et-FerroTANE = 1,1'-bis((2R,4R)-2,4-diethyl...
Scheme 32: Nickel-catalyzed arylation of diphenylphosphine 25d.
Scheme 33: Nickel-catalyzed synthesis of (R)-BINAP 116 (dppe = 1,2-bis(diphenylphosphino)ethane, DABCO = 1,4-d...
Scheme 34: Nickel-catalyzed cross-coupling between aryl bromides 119 and diphenylphosphine (25d) (dppp = 1,3-b...
Scheme 35: Stereocontrolled Pd(0)−Cu(I) cocatalyzed aromatic phosphorylation.
Scheme 36: Preparation of alkenylphosphines by hydrophosphination of alkynes.
Scheme 37: Palladium and nickel-catalyzed addition of P–H to alkynes 125a.
Scheme 38: Palladium-catalyzed asymmetric hydrophosphination of an alkyne 128.
Scheme 39: Ruthenium catalyzed hydrophosphination of propargyl alcohols 132 (cod = 1,5-cyclooctadiene).
Scheme 40: Cobalt-catalyzed hydrophosphination of alkynes 134a (acac = acetylacetone).
Scheme 41: Tandem phosphorus–carbon bond formation–oxyfunctionalization of substituted phenylacetylenes 125c (...
Scheme 42: Organolanthanide-catalyzed intramolecular hydrophosphination/cyclization of phosphinoalkynes 143.
Scheme 43: Hydrophosphination of alkynes 134c catalyzed by ytterbium-imine complexes 145 (hmpa = hexamethylpho...
Scheme 44: Calcium-mediated hydrophosphanylation of alkyne 134d.
Scheme 45: Formation and substitution of bromophosphine borane 151.
Scheme 46: General scheme for a nickel or copper catalyzed cross-coupling reaction.
Scheme 47: Copper-catalyzed synthesis of alkynylphosphines 156.
Radical zinc-atom-transfer-based carbozincation of haloalkynes with dialkylzincs
- Fabrice Chemla,
- Florian Dulong,
- Franck Ferreira and
- Alejandro Pérez-Luna
Beilstein J. Org. Chem. 2013, 9, 236–245, doi:10.3762/bjoc.9.28
- little impact on the efficiency and diastereoselectivity of vinyl halide formation (Table 1, entries 6 and 7). Reaction of Et2Zn with 3a provided vinyl bromide 4aa in 39% yield (78:22 Z/E ratio) and 5a in 17% yield, while reaction of n-Bu2Zn gave 4ab in 37% yield (76:24 Z/E ratio) and 5b in 12% yield. It
Graphical Abstract
Scheme 1: Anticipated formation of alkylidene zinc carbenoids by reaction of dialkylzincs with β-(propargylox...
Scheme 2: Preparation of β-(propargyloxy)enoates having pendant haloalkynes. Reagents and conditions: (a) 2 (...
Scheme 3: Possible reaction pathways to account for the formation of product 5.
Scheme 4: Test experiments to gain insight into the mechanism of formation of alkylidene zinc intermediate 7.
Scheme 5: Mechanistic rationale for the reaction of dialkylzincs with β-(propargyloxy)enoate 3a.
Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine
- Supriya Dey and
- Narayanaswamy Jayaraman
Beilstein J. Org. Chem. 2012, 8, 522–527, doi:10.3762/bjoc.8.59
- methodology include the formation of vinyl halide, vinyl ether, diketone and diol intermediates, which are potential sites for varied types of functionalizations. While exploring such features, we undertook the preparation of septanoside derivatives that are branched out at C-2, so as to afford 2-deoxy-2-C
- oxygen at C-2 of oxyglycal I was retained throughout until the septanoside V was obtained. More importantly, vinyl halide III and diketone IV also form as intermediates of the reaction and these intermediates provide an avenue to expand the scope of the reaction sequence. In the present work, we
- envisaged that III would form as a synthon to implement C–C bond forming reactions. Vinyl halide 2 was synthesized through a ring-expansion reaction of cyclopropanated adduct 1 (Scheme 1), as reported previously [21]. The reactivity at C-2 of 2 was examined by the chosen organometallic reactions, namely
Graphical Abstract
Figure 1: Synthetic route to transform oxyglycal I to a septanoside V.
Scheme 1: Reaction conditions: (i) NaOMe, PhMe, reflux, 8 h; (ii) methyl acrylate (for 3); tert-butyl acrylat...
Scheme 2: Reaction conditions: (i) phenylboronic acid (for 8); 4-methoxyphenylboronic acid (for 9); 3-methylp...
Scheme 3: Reaction conditions: (i) phenylacetylene (for 11); oct-1-yne (for 12); Pd(PPh3)2Cl2 (20 mol %), CuI...
Scheme 4: Reaction conditions: (i) Pd/C (10 %), H2, MeOH, rt, 24 h; (ii) NaBH4, MeOH, 0 °C to rt, 3 h.
