Stereoselective synthesis of #beta#-C-D-glucopyranosides using the reaction of TMSCN and Grignard reagents with cyclic five-membered sulfonium salt intermediates

摘要

In the presence of a Lewis acid,ArSCl adducts of tri-O-benzyl-D-glucal react with vinyl ethers to form cyclic five-membered sulfonium salt intermediates.The latter are capable of reacting with TMSCN and Grignard reagents sfurnishing exclusively 2-S-(aryl)-2-tio-#beta#-C-D-glucopyranosides.The one-pot reaction also proceeds with high stereoselectivity of C-C bond formation in the lateral chain providing exclusively or predominantly C-glycosides with (S)-configuration of the chiral center in the lateral chain.