Abstract
Alkylidenecycloalkanes 1 undergo two sequential Me2AlCl-catalyzed ene reactions with ,/3-unsaturated carbonyl compounds to give bicyclic alcohols 3. At low temperatures, the initial ene adducts 2 can be isolated when vinyl ketones are used. This reaction has been used for the synthesis of 24-oxocholesterol. Other classes of alkenes give more complex mixtures. The scope, limitations, and mechanism of this reaction are discussed.