General, stereoselective synthesis of ethylene isosteres of α- and β-glycosylasparagines

The coupling of α- or β-d-linked lithium C-glycosyl acetylides with N-Boc d-serinal acetonide followed by the reduction of the triple bond, deoxygenation, and oxidative cleavage of the oxazolidine ring afforded α- and β-anomer pairs of C-glycosyl α-aminopentanoic acids (gluco, manno, galacto, and 2-acetamido-galacto).