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  • Enantio- and Regioselective...
    Ma, Jun-Bao; Zhao, Xia; Zhang, Dongju; Shi, Shi-Liang

    Journal of the American Chemical Society, 08/2022, Letnik: 144, Številka: 30
    Journal Article

    Direct asymmetric functionalization of the pyridyl C–H bond represents a longstanding challenge in organic chemistry. We herein describe the first enantioselective para-C–H activation of pyridines through the use of a Ni–Al bimetallic catalyst system and N-heterocyclic carbene (NHC) ligand for intermolecular hydroarylation of styrenes. The reaction procceds in high to excellent enantioselectivities (up to 98.5:1.5 er) and high site-selectivities for both styrene and pyridine components (up to >98:2). Consequently, a broad range of enantioenriched 1,1-diarylalkanes containing pyridine moieties could be prepared in a single step with 100% atom economy. Computational studies supported a mechanism involving a ligand-to-ligand H-transfer (LLHT) and reductive elimination sequence, with LLHT being the rate- and enantioselectivity-determining step. DFT studies indicate that the π–π stacking interaction between the NHC aryl fragment and trans-styrenes is critical for high reactivity and enantiocontrol.