Selective C-O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers' Borane Generated In Situ.

Described herein is the selective reduction of sugars with hydrosilanes catalyzed by using Piers' borane [(C6 F5 )2 BH] generated in situ. The hydrosilylative C-O bond cleavage of silyl-protected mono- and disaccharides in the presence of a (C6 F5 )2 BH catalyst, generated in situ from (C6 F5 )2 BOH, takes place with excellent chemo- and regioselectivities to provide a range of polyols. A study of the substituent effects of sugars on the catalytic activity and selectivity revealed that the steric environment around the anomeric carbon (C1) is crucial.