Catalytic Enantioselective Cross-Couplings of Secondary Alkyl Electrophiles with Secondary Alkylmetal Nucleophiles: Negishi Reactions of Racemic Benzylic Bromides with Achiral Alkylzinc Reagents
Author(s)Cordier, Christopher J.; Fu, Gregory C.; Binder, Jorg T.
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We have developed a nickel-catalyzed method for the asymmetric cross-coupling of secondary electrophiles with secondary nucleophiles, specifically, stereoconvergent Negishi reactions of racemic benzylic bromides with achiral cycloalkylzinc reagents. In contrast to most previous studies of enantioselective Negishi cross-couplings, tridentate pybox ligands are ineffective in this process; however, a new, readily available bidentate isoquinoline–oxazoline ligand furnishes excellent ee’s and good yields. The use of acyclic alkylzinc reagents as coupling partners led to the discovery of a highly unusual isomerization that generates a significant quantity of a branched cross-coupling product from an unbranched nucleophile.
DepartmentMassachusetts Institute of Technology. Department of Chemistry
Journal of the American Chemical Society
American Chemical Society (ACS)
Binder, Jorg T., Christopher J. Cordier, and Gregory C. Fu. “Catalytic Enantioselective Cross-Couplings of Secondary Alkyl Electrophiles with Secondary Alkylmetal Nucleophiles: Negishi Reactions of Racemic Benzylic Bromides with Achiral Alkylzinc Reagents.” Journal of the American Chemical Society 134, no. 41 (October 17, 2012): 17003-17006.
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