Amine-catalyzed direct Diels–Alder reactions of α,β-unsaturated ketones with nitro olefins

Amine-catalyzed Diels–Alder reactions of α,β-unsaturated ketones with dienophiles have been developed. Either (S)-1-(2-pyrrolidinylmethyl)pyrrolidine or l-proline catalyzed the in situ-generation and reaction of 2-amino-1,3-dienes to provide cyclohexanone derivatives in good yield (up to 87%) in one step with modest enantioselectivity.