Thioanisole reaction with carbonyl compounds

Deprotonadon of thioanisole and addition of a carbonyl compound affords an isolable hydroxy sulfide which can then be alkylated (Scheme 7). Treatment with base generates the same betaine that would have been formed using the sulfur ylide approach, and effects the intramolecular displacement reaction. The addition of methylthiomethyllithium to 2-cyclohexenone exclusively provides the 1,2-addition prod-uct the dianions derived from phenylmethanethiol or allylthiol react in a similar manner. In one case a 6-keto steroidal substrate was found to undergo smooth methylenation using this procedure. 

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