Synthesis of methyl alpha-L-vancosaminide

The synthesis of methyl alpha-L-vancosaminide from di-O-acetyl-L-rhamnal is described. The allylic alcohol methyl 2,3,6-trideoxy-3-C-methyl-alpha-L-th reo-hex-2-enopyranoside was prepared from the glycal, 1,5-anhydro-1,2,6-tri deoxy-3-C-methyl-L-ribo-hex-1-enitol, and converted to its N,N-dimethylisou rea derivative. The cis amino alcohol functionality in vancosamine was intr oduced by the electrophilic cyclization of the isourea, followed by hydroly sis of the resulting oxazoline. (C) 2000 Elsevier Science Ltd. All rights r eserved.