Phosphorus in organic synthesis. XVI. Diphenyl phosphorazidate (DPPA) and diethyl phosphorocyanidate (DEPC). Two new reagents for the preparation of thiol esters from carboxylic acids and thiols.

Abstract

Thiol esters were directly and conveniently prepared from carboxylic acids and thiols with diphenyl phosphorazidate (DPPA) or diethyl phosphorocyanidate (DEPC) in the presence of triethylamine in dimethylformamide solution. Both aromatic and aliphatic acids easily react with both aromatic and aliphatic thiols. The method can be efficiently applied to the thiol ester synthesis with little racemization, demonstrated by the formation of ethyl thiol ester of benzoyl-L-leucine.