Alcohols, secondary, conversion into with chlorine

Alkyl Chlorides from Alcohols and Ethers. The reaction of Ph3PCl2 with alcohols provides an excellent synthetic method for the preparation of alkyl chlorides. Mechanistic studies suggest the rapid initial formation of an alkyloxyphosphonium intermediate which then undergoes slow conversion into Ph3PO and alkyl chloride (eq 1). It is assumed that chlorination takes place by an Sn2 reaction in most cases thus, inversion of configuration is observed in the transformation of (—)-menthol to (+)-neomenthyl chloride (eq 2). As illustrated in eq 1, primary, secondary, and even tertiary alcohols are chlorinated with PhsPCb, although reactions of tertiary alcohols are often accompanied by elimination (10%). 

Synthesis.—Corey has published a complementary paper to his earlier description of the specific conversion of allylic alcohols into halides (see p. 196) treatment of primary or secondary alcohols with dimethyl sulphide and iV-chlorosuccinimide (or chlorine itself) leads to high yields of the corresponding carbonyl compound (Scheme 69). 

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