A Convenient Synthesis of Chiral Oxazolidin-2-Ones and Thiazolidin-2-Ones and an Improved Preparation of Triphosgene

Abstract

Abstract Oxazolidin-2-ones and thiazolidin-2-one are conveniently prepared by condensation of L-serine, L-threonine and L-cysteine, respectively with triphosgene. The corresponding methyl esters may be subsequently obtained by quenching the reaction mixture with methanol, without prior need for the isolation of the free acids. An improved procedure for preparation of triphosgene using an internal cooling system is described.