Aryl 1-chloroalkyl sulfoxides as acyl anion equivalents: a new synthesis of vinyl sulfides, ketones, and diketones from aryl 1-chloroalkyl sulfoxides and α,ω-dichloro-α,ω-disulfinylalkanes

Treatment of aryl α-chloroalkyl sulfoxides, which were synthesized from aryl 1-chloroalkyl sulfoxides by alkylation with iodoalkanes, with trifluoroacetic anhydride and NaI in acetone at low temperature afforded vinyl sulfides in high yields. The vinyl sulfides were converted to ketones by hydrolysis with HClO4 in refluxing 1,4-dioxane in good yields. In this procedure, the lithiated aryl 1-chloroalkyl sulfoxides acted as acyl anion equivalents. The procedure was extended to a synthesis of α,ω-diketones starting from α,ω-dichloro-α,ω-disulfinylalkanes. The procedure was found to work well when the length of the carbon chain of the α,ω-disulfinylalkanes is longer than four, and the yields of the diketones were found to be somewhat variable (60–80%).