Tetrahedron

N-Heterocyclic carbenes: deducing σ-and π-contributions in Rh-catalyzed hydroboration and Pd-catalyzed coupling reactions

…, EL Rosen, AV Joyce, PD Vu, VM Lynch, CW Bielawski

文献索引：Khramov, Dimitri M.; Rosen, Evelyn L.; Er, Joyce A.V.; Vu, Peter D.; Lynch, Vincent M.; Bielawski, Christopher W. Tetrahedron, 2008 , vol. 64, # 29 p. 6853 - 6862

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被引用次数: 92

摘要

The effect of tuning the electronic properties of N-heterocyclic carbene (NHC) ligands was evaluated in multiple, mechanistically distinct, metal-mediated reactions. Hydroboration and Heck reactions, catalyzed by Rh–NHC and Pd–NHC complexes, respectively, were found to result in yields that were up to ten times lower when π-withdrawing substituents were incorporated into the NHC backbone relative to analogues bearing σ-withdrawing groups.