A Synthesis of l-Vancosamine Derivatives from Non-Carbohydrate Precursors by a Short Sequence Based on the Marshall, McDonald, and Du Bois Reactions

The carbamate-protected l-vancosamine glycal, viewed as a universal precursor for vancosamine derivatives, was prepared by a short scheme
based on diastereoselective addition of an allenyl stannane to a lactaldehyde ether, the tungsten-catalyzed alkynol cycloisomerization, and the
rhodium-catalyzed C−H insertion of a carbamate nitrogen. This sequence is a prototype for a new and efficient strategy for the synthesis of
3-amino sugar derivatives. The key intermediate was elaborated to the silyl ether of N,N-dimethyl vancosamine glycal.