Enantioselective Copper-Catalyzed Conjugate Addition to Trisubstituted Cyclohexenones: Construction of Stereogenic Quaternary Centers

Trimethyl- and triethylaluminum undergo enantioselective conjugate addition to 3- and 2-substituted cyclohexenones in the presence of catalytic amounts of a Cu salt and a phosphoramidite ligand L* (see scheme). Thus, chiral quaternary centers can be built with up to 96.6 % ee. Functionalized enones lead to bicyclic structures by a subsequent aldol reaction.