Asymmetric Synthesis of 4-Amino-2,3,4- trideoxyaldonic Acids: Novel GABA C-Glycoconjugates

Stereochemically defined 4-amino-2,3,4-trideoxyaldonic acids 4, representatives of a new progeny of C-glycosylated GABAs, have been synthesized from the readily available aldehydo precursors 1 in three steps and 60-75% overall yields. The key reaction is the SnCl4-assisted regio- and diastereoselective homologation of 1 with the nitrogen-containing five-membered ring siloxydiene TBSOP