Reaction of 1,2-trans-glycosyl acetates with phosphorus pentachloride: new efficient approach to 1,2-trans-glycosyl chlorides

Reaction of phosphorus pentachloride with 1,2-trans-glycosyl esters is described. The reaction mechanism presumably involves formation of a tetrachlorophosphonium ion as one of the key reactive intermediates, which can be induced either by Lewis acids or by using acetonitrile as the reaction solvent. Two novel, efficient methods for the synthesis of the thermodynamically unstable glycosyl chlorides were developed based on this reaction.