Synthesis of unsaturated C-glycosyl glycines

Palladium(0)-catalyzed alkylation of 2,3-unsaturated aryl glycoside with et hyl nitroacetace or N-(dipheuylmethylene)glycine ethyl ester in the presenc e of N,O-bis(trimethylsilyl)acetamide/KOAc afforded ethyl 2-(4,5-di-O-benzy l-2,3-dideoxy-alpha -D-erythro-hex-2-enopyranosyl)-2(R,S)-nitroacetate (2) and ethyl 3-(4,6-di-O-benzyl-2,3-dideoxy-alpha -D-erythro-hex-2-enopyranosy l)-2(R,S)-[(N-diphenylmethylene)amino)]acetate (7), respectively. Hydrogena tion of compound 2 afforded the saturated aminoesters, while compound 7 was readily transformed into 2-(4,6-di-O-benzyl-2,3-dideoxy-alpha -D-erythro-h ex-2-enopyranosyl)-2(R,S)-glycine (10) by acidic hydrolysis followedby sapo nification.