Synthesis of 2-C- and 3-C-Aryl Pyranosides

Abstract
Lithium diphenylcuprate treatment of methyl 2,3-anhydro-4,6-O-benzylidene-D-pyranosides in which the anomeric substituent and the three-membered rings are cis oriented furnished the expected trans-diaxial opening products. When the relationship between the anomeric group and the epoxide was trans, the same experimental conditions led only to recovered starting material. Cyano cuprates of the type R2CuCNLi2 added stereoselectively to carbohydrate ketones at C-2 and C-3 from the opposite side relative to the anomeric substituent.