
%0 Journal Article
%A Guthrie, RD 
%A Jenkins, ID 
%T Epoxidation with triphenylphosphine and diethyl azodicarboxylate. II. Methyl 4,6-O-benzylidene-D-aldohexopyranosides
%J Australian Journal of Chemistry
%D 1981/09/01
%V 34
%N 9
%P 1997-2000
%K 
%R https://doi.org/10.1071/CH9811997
%U https://www.publish.csiro.au/paper/CH9811997 
%X Epoxidation of the conformationally rigid diaxial diol methyl 4,6-O-benzylidene-&#945;-D-altropyranoside with triphenylphosphine and diethyl azodicarboxylate proceeds in high yield under very mild conditions to give the corresponding 2,3-anhydro-D-mannoside. By contrast, the corresponding diequatorial diol, methyl 4,6-0-benzylidene-&#945;-D-glucopyranoside, undergoes epoxidation only under forcing conditions and gives the D-allo isomer. Evidence is presented for the formation of a cyclic phosphorane intermediate in the latter case. 
