The Pummererrearrangement of 1-deoxy-5-thioglucopyranose derivatives carrying acetonides at the C3,4-positions proceeded regioselectively at the C1 position by treating with TFAA in the presence of pyridine. Studies employing deuterium-labelled derivatives revealed that the reaction was induced by E2 1,2-elimination of trifluoroacetic acid of the trifluoroacetoxy sulfonium intermediate. This methodology
The Pummererrearrangement of 3,4-O-isopropylidene-1-deoxy-5-thiopyranose oxide derivatives took place at the C1 position regioselectively to give the corresponding 5-thiopyranoses. The reaction mechanism of this reaction is also discussed.