in the presence of a base (n-BuLi or KH) gave three-, four-, five-, and six-membered 1-methylsulfinyl-1-methylthiocycloalkanes. These cyclization products were easily converted to the corresponding ketones by acid hydrolysis except 1-methylsulfinyl-1-methylthiocyclopropane which afforded a complicated mixture. The combination of the cyclization with the acid hydrolysis thus provides a new method for