Ketone 4-chloroalkyl phenyl

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. 

Tertiary halides, acetates and methyl ethers, aryl-activated secondary halides, prenyl halides and acetates, acetals, ketals, thioacetals, a-chloroalkyl ethers, and, particularly, a-chloroalkyl phenyl sulrides have been widely used as alkylating agents. Such reagents may contain a variety of functional groups including alkenes, esters, halides, ketones, nitro groups and silyl ethers. 

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