Lithium Triflate as a New Promoter of Glycosylation Under Neutral Conditions¹

1. Presented at the French Chemical Society Meeting, Palaiseau, Sept. 1995.

Abstract

The glycosyl donors 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl trichloroacetimidate and 3,4,6-tri-O-benzyl-α-D-fucopyranosyl trichloroacetimidate were activated under neutral conditions with a catalytic amount (0.05 equiv) of lithium triflate and reacted with a series of alcohols including an acid sensitive sugar to give the corresponding glycosides in high yields. The stereoselectivity of the glycosylation was improved by introducing a participating group next to the anomeric position.

1. Presented at the French Chemical Society Meeting, Palaiseau, Sept. 1995.

Notes

1. Presented at the French Chemical Society Meeting, Palaiseau, Sept. 1995.

The known compounds 3, 4, 5 and 6 were obtained following the general method as described for compounds 9 or 11. They were characterized by ¹H and ¹³C NMR. Their spectra were found to be identical with those described in the literature for 3,¹⁸ 4,¹⁹ 5,²⁰ and 6.²¹