Synthesis of Trimethyl α-Keto Trithioorthoesters and Dimethyl α-Keto Dithioacetals by Reaction of Acyl Chlorides, Anhydrides, Thiol Esters, and N,N-Dimethylamides with [Tris(methylthio)methyl]lithium

摘要

Trimethyl α-keto trithioorthoesters 8 and dimethyl α-keto dithioacetals 7 belong to two interesting classes of compounds able to be used as intermediates in organic synthesis. In particular, the aromatic trithioorthoesters 8 have recently been employed as key intermediates for the realization of a new procedure for the synthesis of α-arylpropionic acids, several of which exhibit remarkable analgesic and antiinflammatory activities. We have already made a mechanistic and applicative study on the reactions of [tris(methylthio)-methyl]lithium (6) with esters 1 (Scheme 1), and we arrived at one-pot reactions able to realize, easily and in excellent yield, the trithioorthoesters 8 or, depending on the conditions used, the dithioacetals 7.