Enantiomerically Pure alpha,beta-Unsaturated Five-Membered-Ring Aldehydes by Ring Contraction of Epoxyhexopyranosides.
A series of epoxyhexopyranosides, variously substituted in the 6-position, were each transformed by ring contraction into a single, enantiomerically pure, alpha,beta-unsaturated furanosidic aldehyde. Similar ring contraction of a C-propylglycosidic analog of one of the epoxyhexopyranosides gave a mixture of two diastereomeric aldehydes. This finding supports the previously suggested mechanism of the reaction and indicates that O-glycosidic epoxypyranosides also rearrange into two aldehydes, one of which is unstable.
Pontén
Fritiof
F
Organic Chemistry 2, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, S-221 00 Lund, Sweden.
Magnusson
Göran
G