Conjugate additions with the efficient monoorganocopper-iodotrimethylsilane combination, exemplified mainly with methylcopper, butylcopper, and tert-butylcopper, proceed cleanly, smoothly, and rapidly to a variety of a, B-unsaturated carbonyl compounds; cyclic and acyclic enones, 8-alkoxy enones, enoates and lactones in ether, THF, and dichloromethane, often at-78 OC. The RCu-(Li1)-TMSI reagent gives a good economy of group transfer with ...
