Syntheses and reactions of saturated and 2,3-unsaturated vinyl and 1'-substituted-vinyl glycosides

Article abstract of DOI:10.1016/0008-6215(92)84153-J

Reaction of tetra-O-acetyl-α-D-glucopyranosyl bromide with bis(acylmethyl)mercurys [Hg(CH₂COR)₂] afforded acetylated vinyl [by use of bis(formylmethyl)mercury] or 1'-substituted-vinyl β-D-glucopyranosides 11-13 in high yields. When used together with phenyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-enopyranoside, these reagents gave analogous vinyl 4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranosides 20-23 which, on treatment with Lewis acids, isomerised to the corresponding C-glycosyl compounds, i.e., (4,6-di-O-acetyl-2,3-dideoxy-D-ertyrho-hex-2-enopyranosyl)acetaldehyd e (24,25) or the corresponding glycosylated methyl ketones 26, 27. A new route to C-3-branched glycals involves treatment of the above thioglycoside or the unsaturated vinyl glycosides with bis(benzoylmethyl)-mercury. Reaction of tetra-O-acetyl-α-D-glucopyranosyl bromide with bis(acylmethyl)mercurys [Hg (CH₂COR)₂] afforded acetylated vinyl [by use of bis(formylmethyl)mercury] or 1′-substituted-vinyl β-D-glucopyranosides 11-13 in high yields. When used together with phenyl 4 ,6-di-O-acetyl-2,3-dideoxy -1-thio-α-D-erythro -hex-2-enopyranoside, these reagents gave analogous vinyl 4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranosides 20-23 which, on treatment with Lewis acids, isomerised to the corresponding C-glycosyl compounds, i.e., (4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranosyl) acetaldehyde (24,25) or the corresponding glycosylated methyl ketones 26, 27. A new route to C-3-branched glycals involves treatment of the above thioglycoside or the unsaturated vinyl glycosides with bis(benzoylmethyl)-mercury.