Allylic lithiation of methylenecyclobutanes

Abstract: Methylenecyclobutanes undergo a lithiation reaction in the presence of n-BuLi or n-BuLi/KO t Bu from −78°C to room temperature or to 40°C in THF within 3h and then quenching with a variety of electrophiles to give the corresponding addition products (alcohols) in moderate to good yields within 2h. The alcohols can be easily oxidized to the ketones, which can be transformed to the substituted cyclopentenes in the presence of AlCl3 within short reaction time. [Copyright &y& Elsevier]