An approach to the highly stereocontrolled synthesis of α-glycosides.: Compatible use of the very acid labile dimethoxytrityl protecting group with Yb(OTf)3-promoted glycosidation

The very acid labile dimethoxytrityl group is demonstrated to survive Yb(OTf)(3)-promoted glycosidations with N-phenyl trifluoroacetimidates as the donors. In addition, the installation of this sterically demanding protecting group at the primary position of the donor allows the achievement of a very high selectivity in the synthesis of alpha-glycosides with a variety of saccharidic acceptors. (C) 2003 Elsevier Ltd. All rights reserved.