Catalytic Enantioselective Diels-Alder Reaction of Dienes with Acyclic and α,β- and β,β-Disubstituted Enones

Despite the wealth of methods to enantioselectively catalyze Diels-Alder reactions of α,β-unsaturated carbonyl dienophiles, until today, not a single example with an acyclic enone that is either β,β- or α,β-disubstituted has been reported. Herein, we disclose a general Brønsted acid-catalyzed enantioselective Diels-Alder reaction of various aliphatic acyclic disubstituted enones with hydrocarbon dienes featuring diverse steric and electronic properties. The established method has been employed to synthesize several enantiopure targets, including well-known fragrance components such as arborone and the damascones.