Stereoselective synthesis of 2-C-acetonyl-2-deoxy-D-galactosides using 1,2-cyclopropaneacetylated sugar as novel glycosyl donor.

1,2-Cyclopropaneacetylated sugar is an effective glycosyl donor, which reacted with various glycosyl acceptors including monosaccharides, amino acids and other alcohols in the presence of BF(3)*OEt(2) or TMSOTf. The glycosylation is stereoselective in favor of beta-anomeric products with BF(3)*OEt(2) as catalyst, whereas TMSOTf-catalyzed glycosylation prefers the alpha-anomeric products. 2-C-Acetonyl-2-deoxy-D-galactosides were obtained in good yields.