Base-Metal Catalysis - presented by Prof. Lingling Chu and Assoc. Prof. Ming Joo Koh and Prof. Zhan Lu and Assoc. Prof. Tatsuhiko Yoshino and Prof. Naohiko Yoshikai

Base-Metal Catalysis

Lingling Chu, Ming Joo Koh, Zhan Lu and Tatsuhiko Yoshino

Prof. Lingling ChuAssoc. Prof. Ming Joo KohAssoc. Prof. Tatsuhiko YoshinoProf. Zhan Lu
Slide at 18:48
Stereoselective Control of Radicals via Nickel Established mode for radical mediated Ni-catalyzed enantioselective couplings Challenge: reversible Ni-C bond homolysis renders facially selective addition impractical for asymmetric induction AG+ = 6.5 kcal/mol reversible Ni!! Ni-C bond homolysis favored radical homolysis preferential R.E. Enantioconvergent cross-couplings & cross-electrophile couplings (representative work by Fu, Reisman, etc) Current approach: Reductive Elimination (R.E.) as the stereodetermining step Enhanced difficulty to achieve high enantioselectivity Increased demand for the design of complex chiral ligands Limited substrate scope and structural diversity Fu, G. C. * Science 2017, 356, eaaf7230; Jarvo, E. R. *, Nat. Rev. Chem, 2017, 1. 65. 2014, 509, 299. Jamison, T. F. * Nature 2014, 509, 299.
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References
  • 1.
    J. Choi and G. C. Fu (2017) Transition metal–catalyzed alkyl-alkyl bond formation: Another dimension in cross-coupling chemistry. Science
  • 2.
    E. L. Lucas and E. R. Jarvo (2017) Stereospecific and stereoconvergent cross-couplings between alkyl electrophiles. Nature Reviews Chemistry
  • 3.
    S. Z. Tasker et al. (2014) Recent advances in homogeneous nickel catalysis. Nature
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Summary (AI generated)

Over the last several years, we have developed two strategies to address this challenge: the Chelation strategy and the Sensitization strategy. The Chelation strategy aims to provide alternative or more complicated sterlings in the relation strategy by establishing a direct relation between the pendent functional group and the NCO, which facilitates the LG radical to selectively add to the N center to form a three species. Chelation also benefits from forming a more rigid NCO complex with a favorite Reda elimination that may impede the reverse for eco carbon in the Sensitization strategy.

In the Sensitization strategy, the photoexcitation of the planar ground state need to complex with light will bring the NN two species from its planar to its exact state.