Palladium catalyzed decarboxylative β-C-glycosylation of glycals with oxazol-5-(4H)-ones as acceptors

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 beta-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.

Automated summary

Despite the increasing importance of C-glycosides in biochemistry, the strategies for achieving stereoselective C-glycosidic bond formation have received less attention compared to those for O- and N-glycosides. In this study, a beta-C-glycosylation of oxazol-5(4H)-ones, which serve as direct precursors of amino acids, was described. Regardless of the glycal donors and glycosyl acceptors used, the reaction displayed excellent efficiency and chemoselectivity in most cases without the need for exogenous bases. The outstanding stereocontrol at the anomeric center was attributed to the steric hindrance imposed by a bulky phosphine ligand.