![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
Evaluation of Elementary Steps in Csp2-Csp3 Cross-Electrophile Coupling Reactions Mediated by a Common Ni Complex
Hunter F Starbuck1, Long P Dinh1, Dipannita Kalyani2
1Department of Chemistry and Biochemistry, The Ohio State University, 151 W Woodruff Avenue, Columbus, Ohio 43210, United States.
Abstract:
Cross-electrophile coupling (XEC) reactions are widely employed to rapidly construct C(sp2)-C(sp3) bonds from available substrates. Key elementary steps of the reaction, such as oxidative addition and radical coupling, have been individually investigated with discrete complexes, but no studies exist that probe these and other key steps along the reaction pathway from a single, synthetically relevant platform. This work leverages the accessibility of persistent organonickel complexes to benchmark the effects of electronic and steric parameters of complexes and substrates on the rates of oxidative addition, the stabilities of organonickel intermediates, and the rates of radical coupling. Insights into the rates of oxidative addition help to rationalize synthetic limitations that are frequently encountered in Ni-catalyzed methodologies. Finally, the aggregate effects of the independently studied steps were evaluated by measuring the overall yields of the combinatorial coupling reactions. These insights established guidelines for selecting Ni complexes for XEC reactions of substrates that are challenging to couple.
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