Organocatalytic asymmetric [4 + 2] formal cycloadditions of cyclohexenylidenemalononitriles and enals to construct chiral bicyclo[2.2.2]octanes

A highly regio- and stereoselective [4 + 2] formal cycloaddition process of cyclohexenylidenemalononitriles and α,β-unsaturated aldehydes has been developed by the catalysis of a chiral secondary amine, affording a range of bridged bicyclo[2.2.2]octane architectures with high molecular complexity (up to 98% ee, >19:1 d.r.).