Preparation of 2,6‐anhydro‐3‐deoxyhept‐(or hex‐)2‐enononitriles (1‐cyanoglycals) from 1‐bromo‐D‐glycosyl cyanides with zinc under aprotic conditions

Abstract

AbstractAcetylated 1‐bromo‐D‐glycosyl cyanides 1–5 react with zinc dust in acetic acid, acetic acid/water, or 2‐propanol to give mixtures of acetylated 1‐cyanoglycals 6–9 and anomeric pairs of glycosyl cyanides 10–14. Reaction of 1–5 in refluxing benzene in the presence of one equivalent of triethylamine or especially pyridine predominantly leads to the formation of 1‐cyanoglycals.