A novel synthetic approach to C-glycosyl-D- and L-alanines

C-Glycosyl-(S)- and (R)-alanines 12a and 12b were synthesized from the known beta-C-glycoside 1. The nitrogen function was introduced by aza-Claisen rearrangement of the allylic thiocyanate 7, derived from the corresponding alcohol 6. The absolute configuration of the newly created chiral carbon center (C-3) was assigned by X-ray diffraction analysis of the intermediate 3(S)-isothiocyanato-D-glycero-D-galacto-decose 8a.