Domino Heck/lactonization-catalyzed synthesis of 3-C-linked mannopyranosyl coumarins.
Selective syntheses of methyl alpha- (8) and beta-C-mannopyranosyl acrylates (9) were obtained from alpha-C-allyl mannopyranoside (3) by ozonolysis to 4 followed by alpha-methylenation to provide intermediate aldehydes 5 and 6. The beta-anomer 6 was obtained by in situ anomeric epimerization. The acrylates and the homologous alpha-anomer 16, obtained by oxidative hydroboration, oxidation, and alpha-methylenation, were converted into 3-C-linked mannopyranosyl coumarins 11, 12, and 19 in good yields under one-pot Heck/lactonization conditions.
Giguère
Denis
D
Department of Chemistry, Université du Quebec à Montréal, P.O. Box 8888, Succ. Centre-Ville Montréal, QC, Canada H3C 3P8.
Cloutier
Philipe
P
Roy
René
R