cis-Enals in N-heterocyclic carbene-catalyzed reactions: distinct stereoselectivity and reactivity

The first successful generation of cis-homoenolate equivalents from cis-enals under the catalysis of N-heterocyclic carbenes (NHCs) has been realized. The cis-homoenolate intermediates undergo effective reactions with α,β-unsaturated imines to afford chiral cyclic ketone products. Compared to the trans-enals, cis-enals show different stereoselectivities and new reactivity patterns.