1-chloroalkyl p-tolyl sulfoxides

Finally, the addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxides 154 to carbonyl compounds gave the adducts 155, which were treated with alkyllithium such as f-C4H9Li to afford the one-carbon homologated carbonyls compounds 158, from their lithium enolate forms 157, having an alkyl group at the a-position, via the carbenoid /S-alkoxides 156 (equation 53) °. 

A benzazepine derivative of homopipecolic acid 53 was formed by the reaction of an A-magnesioaryl amine with a magnesium carbenoid formed from 1-chloroalkyl p-tolyl sulfoxide 51. The intermediate 52 was trapped with ethyl chloroformate to yield the benzoazepine in good yield. In contrast, the corresponding azepine derivative was formed in only 4% yield <07TL7829>. 

Asymmetric induction occurs during the alkylation of ketones with the a-sulfinyl carbanion derived from optically active 1-chloroalkyl-p-tolyl sulfoxides (equation 18). The resulting chloro alcohol may be converted to an optically active epoxide under alk ine conditions and the sulfinyl group is removed with n-butyllithium. While the process benefits from high asymmetric induction in the alkylatitm reaction, it must be recognized that, when either R 91H and/or R R diasteretHnerk compounds are formed and require separation. 

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