Short syntheses of enantiopure calystegine B2, B3, and B4

Abstract

Calystegine B2, B3, and B4 have been prepared in 5 steps from the benzyl protected methyl 6-iodoglycopyranosides of glucose, galactose and mannose, respectively, by using a zinc-mediated domino reaction followed by ring-closing olefin metathesis as the key steps.