Homologation of O-Acetylated Methyl Hexopyranosides with a Grignard C1 Reagent

Abstract

Three methyl 2,3,4-tri-O-acetyl-α-D-hexopyranosides of the manno, gluco, and galacto configuration were oxidized to the corresponding methyl hexodialdo-1,5-pyranosides and then reacted with allyloxymethylmagnesium chloride. Methyl heptopyranosides of the D- and L-glycero-α-D-manno-, -α-D-gluco, and -α-D-galacto configuration were obtained in moderate yields. Migration of the 4-O-acetyl group in the products was observed. An interpretation of the results was proposed.