Stereoselective synthesis of beta-1-C-substituted 1,4-dideoxy-1,4-imino-D-galactitols and evaluation as UDP-galactopyranose mutase inhibitors

The synthesis of 1-C-substituted 1,4-dideoxy-1,4-imino-D-galactitols involving nitrone umpolung is described. The SmI(2)-induced key coupling proved highly stereoselective in favor of the beta-C-substituted products bearing a three-carbon chain at the pseudoanomeric position. Pyrrolidines 9 and 10, as well as the bicyclic compounds 8 and 11, exhibit weak inhibition of the activity of the UDP-galactopyranose mutase from Escherichia coli.