Copper-catalyzed tandem conjugate addition-electrophilic trapping: ketones, esters, and nitriles as terminal electrophiles.

Exposure of enone substrates 1a-18a, which possess appendant ketone, ester, and nitrile moieties, to Et2Zn in the presence of catalytic Cu(OTf)2/P(OEt)3 provides the cyclized products in good to excellent yields and diastereoselectivities. These results represent the first use of ketones, esters, and nitriles as terminal electrophiles in Cu-catalyzed conjugate addition-electrophilic trapping.