Synthesis of l-Vancosamine Derivatives from Methyl (alpha)-d-Mannopyranoside

Concise synthesis of l-vancosamine, the amino sugar constituent of vancomycin and other antibiotics, has been achieved. The key steps include (1) stereoselective addition of methylcerium reagent to oximino ether, and (2) stereoselective hydrogenation of 5,6-unsaturated glycoside with C(5) inversion to give l-vancos­amine derivative. C-Glycosidation of vancosaminyl acetate with ­ iodoresorcinol proceeded in the presence of Sc(OTf)3 in high yield.