Metalation reactions. : IV. Metalation of o-alkyl- and o,o′-dialkyl-substituted alkylthiobenzenes

Abstract

Metalation of o-alkyl- and o,o′-dialkylsubstituted alkylthiobenzenes with n-butyllithium, in the presence and absence of TMEDA, has been investigated. The results showed that metalation at the thioalkyl carbon probably occurs by direct attack of the organolithium reagent, although a transmetalation reaction cannot be excluded in some cases. It has also been found that benzylic, thio-methylic, and ring metalation occurs in ether alone, whereas mainly thio-methylic or ring metalation occurs in the presence of TMEDA.