Synthesis of Methyl 6-Deoxy-6-diphenylphosphino-α-D-glucopyranoside: Temperature-Dependence of the Primary O-Tosyl Cleavage Mode

Abstract

Methyl α-D-glucopyranoside is converted to methyl 6-p-toluenesulfonyl-2,3,4-tris-O-trimethylsilyl-α-D-glucopyranoside 2 and then reacted with lithium diphenylphosphide in THF. When the reaction is carried out at room temperature and below, S-O cleavage dominates giving methyl 2,3,4-tris-O-trimethylsilyl-α-D-glucopyranoside 3, whereas at 60°C in THF or at 35°C in diethyl ether, C-O cleavage occurs yielding the title carbohydrate-phosphine 4 in good yield after deprotection.