The Wittig-Horner reaction on 2,3,4,6-tetra-O-benzyl-D-mannopyranose and 2,3,4,6-tetra -O-benzyl-D-glucopyranose

The synthetic utility of the Wittig-Horner reaction in the synthesis of C-glycosides is illustrated by the preparation of the α-and β-glycosyl acetates of the 2,3,4,6-tetra-O-benzyl-D-mannopyranose and of the 2,3,4,6-tetra-O-benzylglucopyranose. A partial epimerization of the C-2 carbon of the starting protected carbohydrate is observed.