A novel synthesis of carboxylic acid derivatives having a quaternary carbon at 3-position and functional groups at 4-position from 1-chlorovinyl p-tolyl sulfoxides and acetic acid esters

Addition of the lithium enolate of acetic acid esters to 1-chlorovinyl p-tolyl sulfoxides, which were derived from ketones and chloromethyl p-tolyl sulfoxide in three steps in good yields, gave carboxylic acid esters having a quaternary carbon at the 3-position, and chlorine and sulfinyl groups at the 4-position in high yields. Various kinds of functionalized carboxylic acid derivatives, including spiro-lactones, were derived from the adducts in good to high yields.