Ni-Cat C–C Bond Formation

tal-catalyzed reactions continue to see widespread use in academic settings as well as in the pharmaceutical industry and for the synthesis of commodity chemicals. As such, a major area of research in the Jamison group is the development of transition-metal-catalyzed methods for the formation of carbon–carbon and carbon–heteroatom bonds with high regio-, diastereo-, and enantioselectivity. These efforts involve nickel(0) catalysts supported by phosphines, phosphites, and N-heterocyclic carbenes for the synthesis of complex molecules from simple feedstocks such as alkynes, α-olefins, epoxides, and aldehydes.

The Jamison Laboratory is active in the development of substitution reactions employing simple alkenes as alkenyl metal equivalents. Nickel-catalyzed intermolecular benzylation, heterobenzylation, and allylation (not shown) of unactivated alkenes proceed with high yields and high functional-group tolerance. In contrast to analogous palladium-catalyzed variants, these reactions employ electronically unbiased aliphatic olefins, proceed at room temperature, and provide 1,1-disubstituted olefins with high selectivity.

Another major area of research within Jamison's group is the development of Ni-catalyzed reductive coupling reactions, leading to the formation of highly enantioenriched allylic or homoallylic alcohols and amines, both of which are valuable intermediates in organic synthesis. For an overview of much of our work in the area of reductive couplings.

Recently, we have demonstrated that isopropanol serves as an effective reducing agent for the Ni-catalyzed reductive coupling reactions of alkynes and epoxides. This important advance obviates the requirement for triethylborane and allows the use of air-stable and inexpensive Ni(II) salts in place of Ni(cod)2. Deuterium-labeling studies demonstrated that oxidative addition of an in situ-generated Ni(0) species proceeds at the least hindered C–O bond of the epoxide with inversion of configuration.