A-Chloroalkyl phenyl sulfides

Very good yields, mild conditions, regioselectivity, versatility in the choice of the two reacting species (easy access to thermodynamic versus kinetic silyl enol ethers as well as to the required a-chloroalkyl phenyl sulfides) give to these sequences a particularly wide scope. Neopentylation is one illustration of their utility [325]. 

Phenylthioalkylation of silyl enol ethers. Silyl enol ethers of ketones, aldehydes, esters, and lactones can be alkylated regiospecifically by a -chloroalkyl phenyl sulfides in fhe presence of a Lewis acid. Zinc bromide and titanium(IV) chloride are the most effective catalysts. The former is more satisfactory for enol ethers derived from esters and lactongs. ZnBr2 and TiCL are about equally satisfactory for enol ethers of ketones. The combination of TiCL and Ti(0-f-Pr)4 is more satisfactory for enol ethers of aldehydes. Since the products can be desulfurized by Raney nickel, this reaction also provides a method for alkylation of carbonyl compounds. Of more interest, sulfoxide elimination provides a useful route to a,B-unsaturated carbonyl compounds. 

The a-chloroalkyl phenyl sulfides are prepared by reaction of the corresponding alkyl bromide with sodium thiophenoxide to give an alkyl phenyl sulfide, which is then chlorinated by NCS. 

Treatment of a mixture of nitrile anion 74 and 1-chloroalkyl phenyl sulfides... 

A variety of other functional groups may be present in either the halide or the mercaptan. Olefinic sulfides are obtained by the action of allyl halides on benzyl or phenyl mercaptides. Ethylene, tri-methylene, and 1-pentene chlorohydrins give hydroxyalkyl sulfides, from which chloroalkyl sulfides are obtained by the Darzens procedure (method 33) i -i pbenacyl chloride gives keto sulfides of the type CjHsCOCHjSR. Alkylmercapto acids are prepared from either halo acids... 

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