A concise C-glycosyl amino acid synthesis by alkenylC-glycoside–vinyloxazolidinecross-metathesis. Synthesis of glycosyl serine, asparagine and hydroxynorvaline isosteres

Abstract

A convergent synthesis has been developed to afford C-linked glycosyl amino acids by cross-metathesis of vinyl, allyl, and butenyl C-glycosides with N-Boc-vinyloxazolidine using the Grubbs 1,3-dimesityl-4,5-dihydroimidazol-2-ylideneruthenium carbene. The method has been employed to introduce through an α-linkage, an α-aminopentanoic acid chain at the anomeric carbon of β-D-C-gentiobiose to give a totally artificial glycosyl α-amino acid of a disaccharide. This compound represents the isostere of the α-linked glycosylasparagine moiety of the natural glycopeptide nephritogenoside.