1-cyanovinyl Acetate Research Articles

Bis(1-cyanovinyl acetate) Is a Linear Precursor to 3-Oxidopyrylium Ions.

Herein we describe the first approach to 3-oxidopyrylium ions from a linear precursor. Heating bis(1-cyanovinyl acetate) in the presence of a trace amount of pyridinium p-toluenesulfonate results in a series of acyl group transfers and an intramolecular cyclization event to form a 3-oxidopyrylium ion that can be trapped by reaction with several dipolarophiles. When treated with dienes, the result is a sequential [5 + 2]/[4 + 2] cycloaddition reaction that provides sp3-rich products of high molecular complexity.

Substituent Effects on Regioselectivity of the Diels-Alder Reactions: Reactions of 10-Allyl-1,8-dichloroanthracene with 2-Chloroacrylonitrile, 1-Cyanovinyl Acetate and Phenyl Vinyl Sulfone

Diels-Alder reaction of 10-allyl-1,8-dichloroanthracene (3) with 2-chloroacrylonitrile (4) and 1-cyanovinyl acetate (5) gives exclusively theorthoisomer while its reaction with phenyl vinyl sulfone (10) yields a mixture of two isomeric adducts with priority toorthoisomer. The reactions proceeded under microwave condition in xylene. Configurations of these isomers have been assigned with the help of NMR spectra. The results indicated that the steric effect is dominating toward the isomer regioselectivity in the Diels-Alder reaction of the present compounds.

Mapping Molecular Conformations with Multiple-Mode Two-Dimensional Infrared Spectroscopy

The multiple-mode two-dimensional infrared (2D-IR) spectrum in a broad frequency range from 1000 to 3200 cm(-1) of a 1-cyanovinyl acetate solution in CCl(4) is reported. By analyzing its relative orientations of the transition dipole moments of normal modes that cover vibrations of all chemical bonds, the three-dimensional molecular conformations and their population distributions of 1-cyanovinyl acetate are obtained, with the aid of quantum chemistry calculations that translate the experimental transition dipole moment cross angles into the cross angles among chemical bonds.

Stereoselective Synthesis of 8-Oxabicyclo[3.2.1]octane-2,3,4,6,7-pentols and Total Asymmetric Synthesis of 2,6-Anhydrohepturonic Acid Derivatives and ofβ-C-manno-Pyranosides Suitable for the Construction of (1→3)-C,C-Linked Trisaccharides

Enantiomerically pure (+)-(1S,4S,5S,6S)-6-endo-(benzyloxy)-5-exo-{[(tert-butyl)dimethylsilyl]oxy}-7-oxabicyclo[2.2.1]heptan-2-one ((+)-5) and its enantiomer (−)-5, obtained readily from the Diels-Alder addition of furan to 1-cyanovinyl acetate, can be converted with high stereoselectivity into 8-oxabicyclo[3.2.1]octane-2,3,4,6,7-pentol derivatives (see 23 – 28 in Scheme 2). A precursor of them, (1R,2S,4R,5S,6S,7R,8R)-7-endo-(benzyloxy)-8-exo-hydroxy-3,9-dioxatricyclo[4.2.1.02,4]non-5-endo-yl benzoate ((−)-19), is transformed into (1R,2R,5S, 6S,7R,8S)-6-exo,8-endo-bis(acetyloxy)-2-endo-(benzyloxy)-4-oxo-3,9-dioxabicyclo[3.3.1]non-7-endo-yl benzoate ((−)-43) (see Scheme 5). The latter is the precursor of several protected 2,6-anhydrohepturonic acid derivatives such as the diethyl dithioacetal (−)-57 of methyl 3,5-di-O-acetyl-2,6-anhydro-4-O-benzoyl-D-glycero-D-galacto-hepturonate (see Schemes 7 and 8). Hydrolysis of (−)-57 provides methyl 3,5-di-O-acetyl-2,6-anhydro-4-O-benzoyl-D-glycero-D-galacto-hepturonate 48 that undergoes highly diastereoselective Nozaki-Oshima condensation with the aluminium enolate resulting from the conjugate addition of Me2AlSPh to (1S,5S,6S,7S)-7-endo-(benzyloxy)-6-exo-{[(tert-butyl)dimethylsilyl]oxy}-8-oxabicyclo[3.2.1]oct-3-en-2-one ((−)-13) derived from (+)-5 (Scheme 12). This generates a β-C-mannopyranoside, i.e., methyl (7S)-3,5-di-O-acetyl-2,6-anhydro-4-O-benzoyl-7-C-[(1R,2S,3R,4S,5R,6S,7R)-6-endo-(benzyloxy)-7-exo-{[(tert-butyl)dimethylsilyl]oxy}-4-endo-hydroxy-2-exo-(phenylthio)-8-oxabicyclo[3.2.1]oct-3-endo-yl]-L-glycero-D-manno-heptonate ((−)-70; see Scheme 12), that is converted into the diethyl dithioacetal (−)-75 of methyl 3-O-acetyl-2,6-anhydro-4,5-dideoxy-4-C-{[methyl (7S)-3,5,7-tri-O-acetyl-2,6-anhydro-4-O-benzoyl-L-glycero-D-manno-heptonate]-7-C-yl}-5-C-(phenylsulfonyl)-L-glycero-D-galacto-hepturonate (76; see Scheme 13). Repeating the Nozaki-Oshima condensation to enone (−)-13 and the aldehyde resulting from hydrolysis of (−)-75, a (1→3)-C,C-linked trisaccharide precursor (−)-77 is obtained.

Polypropionate fragments with four contiguous chiral centres from acetone

The Diels-Alder adduct of 2,4-dimethylfuran and 1-cyanovinyl acetate was converted with high stereoselectivity into 1,3,5-trimethylcyclohexen-4,6-diol derivatives that can be cleaved into protected polypropionate fragments.

Highly stereoselective, total synthesis of β-c-hexopyranosyl derivatives

One Diels-Alder adduct of furan to 1-cyanovinyl acetate is converted to 8-oxabicyclo[3.2.1]oct-6-en-2-one which is transformed into β-C-hexopyranosides including 2-deoxy and 2,3-unsaturated derivatives.

Synthesis of 1,1-Bis(3,5-dimethyl-2-furyl)ethene; The Chemo- and Site-Selectivity of Its Cycloadditions

The new polyene 1,1-bis(3,5-dimethyl-2-furyl)ethene (11) was derived from 2,4-dimethylfuran. Its reaction with dienophiles such as maleic anhydride, benzoquinone or 1-cyanovinyl acetate generated exclusively Diels-Alder adducts (9-oxabicyclo[4.3.0]nona-1,7-diene derivatives) involving the exocyclic double bond and one double bond of one furyl unit. The reaction of 11 with didehydrobenzene (benzyne) gave a 7-oxabicyclo[2.2.1]hepta-2,5-diene derivative resulting from the exclusive Diels-Alder addition of one furyl group, whereas dimethyl acetylenedicarboxylate added to 11 giving a mixture of the corresponding 7-oxabicyclo[2.2.1]hepta-2,5-diene and 9-oxabicyclo[4.3.0]nona-1,4,7-triene derivatives. With allenic acid, 11 added in a [2+2] fashion exclusively with its exocyclic double bond giving 2-[3,3-bis(3,5-dimethyl-2-furyl)cyclobutylidene]acetic acid with high selectivity.

Total synthesis of cyclophellitol starting from furan

(±)-Cyclophellitol has been prepared in a highly stereoselective fashion from the Diels-Alder adduct of furan to 1-cyanovinyl acetate.

Synthetic studies on furanoheliangolides. Stereocontrolled construction of the oxygen-bridged tricyclic framework

The heavily functionalized 6,9-epoxycyclodeca[b]furan-11-ones 34 and 37 have been prepared in 13 steps from 4-methyl-2-[(phenylmethoxy)methyl]furan. The key elements of the scheme include a high-pressure Diels-Alder cycloaddition to 1-cyanovinyl acetate, highly regiselective hydroboration, controlled stepwise oxidation to give keto aldehyde 20, and thermal oxy-Cope rearrangement of both 32 and 36b. The prior introduction of a phenylthio substituent provides for the accommodation of different levels of unsaturation at a more advanced stage of furanoheliangolide construction

Highly Stereoselective Synthesis of (±)-Aminobromocyclitol Derivatives from Furan

The Diels-Alder adduct (2-cyano-7-oxabicyclo[2.2.1]-hept-5-en-2-yl acetate) of furan and 1-cyanovinyl acetate was converted to N-[(1RS,2RS,3RS,4SR,6RS)-2,3,4-triacetoxy-6-bromocyclohex-1-yl]benzamide and to N-[(1RS,2RS,3SR,4RS,5SR,6SR)-2,3,4,5-tetraacetoxy-6-bromocyclohex-1-yl]b enzamide with high stereoselectivity.