Organolithium compounds enones

Ordinary carbon nucleophiles such as cyanide or Grignard reagents or organolithium compounds fit the patterns we have described already. They usually give the more stable product by 5 2 or 5 2 reactions depending on the starting material. If we use copper compounds, there is a tendency— no more than that—to favour the 5 2 reaction. You will recall that copper(l) was the metal we used to ensure conjugate addition to enones (Chapter 10) and its use in Sn2 reactions is obviously related. 

The lithio-derivative of 2-phenylthioacetonitrile adds in a conjugate manner with high regioselectivity to cyclic enones. " Seebach reports that organolithium compounds undergo 1,4-addition to enones with sterically protected carbonyl groups in high yield [equation... 

Michael additions of organolithium, Grignard, and diorganozinc reagents to enones and other rt, -unsaturated carbonyl compounds are catalyzed inter alia by copper, nickel and cobalt salts. The best results are obtained with cop-per(I) catalysts, especially those in which copper is bound to a soft , readily polarizable center (sulfur or phosphorus). 

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