Reactions of methyl 4,6- O-benzylidene-2,3-dideoxy-2- C- p- tolylsulfonyl-β- d- erythro-hex-2-enopyranoside and its phenyl analog with several nucleophiles; stereoselective preparation of 3- O-acyl- d- arabino- and d- ribo-hex-1-enitol derivatives

Abstract

Reactions of methyl 2- C- p-tolylsulfonyl-2-enopyranoside ( 6) with nucleophiles (methoxide, nitromethane, 2,4-pentanedione, and ammonia) afforded the β- d- gluco adducts with high stereoselectivity. However, similar treatment of the phenyl analog 11 with sodium borodeuteride, nitromethane, methoxide, and lithium hydroxide led mainly to an S n2′ process to give 1-enitol derivatives having the arabino configuration. Conversely, treatment of 11 with carboxylic acids in pyridine gave the 1-enitol derivatives having the ribo configuration as the major product.