Metallation Reactions. XXXVI. A Study on the Metallation of (Methylthio)- and (Methylsulfonyl)thiophenes

FATTUONI, CLAUDIA;Usai Michele;Cabiddu Maria G.;CADONI, ENZO;De Montis Stefania;Sotgiu Francesca;CABIDDU, MARIA GRAZIA

2007-01-01

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Abstract

Methylthio- and methylsulfonyl thiophenes were polymetallated by n-buthyllithium and superbase (LICKOR) in one-step. 2-(Methylthio)thiophene was bimetallated in 5 and in alpha to the methylthio sulfur atom by superbase. 3-(Methylthio)thiophene was bimetallated in both 2 and 5 positions by the organolithium and trimetallated in these two positions and in alpha to the thioethereal sulfur atom by superbase. 3-(Methylsulfonyl)thiophene was bimetallated in 2 and in alpha to the sulfonyl sulfur atom by the organolithium while the 2-(methylsulfonyl)thiophene underwent degradation in the same conditions.