Palladium catalyzed decarboxylative β-C-glycosylation of glycals with oxazol-5-(4H)-ones as acceptors†
Abstract
Despite the increased importance of C-glycosides in biochemistry, the strategy for creating the C-glycosidic bond stereoselectively has received less attention than that for its O- and N-counterparts. We describe here a β-C-glycosylation of oxazol-5(4H)-ones which are the direct precursors of amino acids. For a wide variety of glycal donors and glycosyl acceptors, this chemistry could be accomplished with excellent efficiency and exquisite chemoselectivity without exogenous bases in most cases. The excellent stereocontrol at the anomeric center originates from the steric hindrance imposed by the bulky phosphine ligand.