posted on 2002-05-24, 00:00authored byAlessandro Dondoni, Giandomenico Mariotti, Alberto Marra
A convergent approach has been developed for the synthesis of C-glycosyl amino acids in which
the glycinyl moiety CH(NH2)CO2H is connected to the anomeric center of the sugar residue by a
three carbon atom tether. Essentially, these compounds are isosteres of N-glycosyl asparagines in
which the amide group has been replaced by an ethylene bridge. Following the coupling of α- or
β-d-linked lithium C-glycoside acetylides with N-Boc d-serinal acetonide (Garner aldehyde), the
resulting adducts were transformed into the final N-Boc-C-glycosyl-α-aminopentanoic acids via
reduction of the triple bond, deoxygenation, and oxidative cleavage of the oxazolidine ring. By this
protocol, 12 C-glycosyl asparagines, six pairs of α- and β-anomers, have been prepared incorporating
the gluco, galacto, manno, and the corresponding 2-acetamido-2-deoxy residues.