NHC-Catalyzed Azadiene Diels-Alder Reaction

Significance

The first NHC-catalyzed Diels-­Alder reaction is described in which a reactive dienophile was generated in situ from a carbene and an α,β-unsaturated aldehyde. In the course of the reaction the dienophiles react with α,β-unsaturated aldimines, leading to chiral dihydropyridinone products in high yields and excellent enantio­selectivities. This is a rare example of a highly enantioselective NHC-organocatalyzed intermolecular C-C bond forming reaction.