Copper Hydride-Catalyzed Tandem 1,4-Reduction/Alkylation Reactions

Exposure of an enone to a catalytic quantity of [CuH(PPh3)]6 in the presence of one of several silyl hydrides (PhMe2SiH, PMHS, HMe2SiOSiMe2H) leads to conjugate reduction with concomitant formation of the corresponding silyl enol ether. Without isolation, treatment of these intermediates with a Lewis acid at low temperatures in the presence of an aldehyde, or with fluoride ion together with an activated halide, affords good yields of the product of 3-component coupling (3-CC) in a single reaction flask.