Organocuprate conjugateaddition reactions involve an electron transfer process without the production of any longlived paramagnetic intermediate species. The reduced organic substrate can be trapped by internal displacement, and from studies of the reaction stoichiometry, a mechanism involving an organocopper(III) intermediate is proposed.
The 1,4-addition of organotitaniumatecomplexes to enones by nickel catalysis is reported. With a methyltitanium atecomplex good yields of conjugate addition to stericallyhinderedenones are achieved. Phenyltitanium atecomplexes react with less sterically encumbered enones to the 1,4-addition products in moderate to high yields.