NICKEL-CATALYZED CONJUGATE ADDITION OF TRIMETHYLALUMINUM TO STERICALLY HINDERED ALPHA,BETA-UNSATURATED KETONES

Nickel acetylacetonate is an efficient catalyst for the 1,4-addition of trimethylaluminum to alpha,beta-unsaturated ketones. The reaction is strongly solvent dependent and gives best results in tetrahydrofuran or ethyl acetate. The reaction is especially useful for the nucleophilic 1,4-methyl transfer to sterically hindered enones. A beta-cuparenone synthesis via conjugate methyl group addition to an enone precursor is described.