A novel general route for the synthesis of C-glycosyl tyrosine analogues

A general method for the synthesis of C-glycosyl amino acids is described here. The stereoisomerically pure tyrosine analogues alpha-L-4 and beta-L-6 are prepared in reasonable overall yields from allyl derivatives 10 and 11. The key step is a benzannulation procedure which is employed in the creation of the aromatic ring that bears the amino acid function.