Regiospecific Synthesis of α-Diones, α,α-Dialkoxyketones and α-Alkoxy-α-sulfenylated Ketones

A convenient synthesis of α-diones and their monoprotected acetals, i.e. α-ketoacetals, was developed by mercury induced solvolysis of regiospecifically formed α-chloro-α-(alkylthio)ketones. Analogously, α-alkoxy-α-sulfenylated ketones were formed when reacting α-chloro-α-sulfenylated ketones with an alkaline alcoholic medium. α-Alkoxy-α-sulfenylated ketones themselves could be transformed into α-diones or α-ketoacetals, which in turn were hydrolyzed under anhydrous conditions into the corresponding α-diones.