Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Department of Chemistry & Biochemistry, University of California, Los Angeles, California 90095, United States.
J Am Chem Soc. 2021 Sep 29;143(38):15873-15881. doi: 10.1021/jacs.1c08105. Epub 2021 Sep 20.
A Ni/photoredox-catalyzed enantioselective reductive coupling of styrene oxides and aryl iodides is reported. This reaction affords access to enantioenriched 2,2-diarylalcohols from racemic epoxides via a stereoconvergent mechanism. Multivariate linear regression (MVLR) analysis with 29 bioxazoline (BiOx) and biimidazoline (BiIm) ligands revealed that enantioselectivity correlates with electronic properties of the ligands, with more electron-donating ligands affording higher ee's. Experimental and computational mechanistic studies were conducted, lending support to the hypothesis that reductive elimination is enantiodetermining and the electronic character of the ligands influences the enantioselectivity by altering the position of the transition state structure along the reaction coordinate. This study demonstrates the benefits of utilizing statistical modeling as a platform for mechanistic understanding and provides new insight into an emerging class of chiral ligands for stereoconvergent Ni and Ni/photoredox cross-coupling.
本文报道了镍/光氧化还原催化的苯乙烯氧化物和芳基碘化物的对映选择性还原偶联反应。该反应通过立体协同机制，从外消旋环氧化物中获得对映体富集的 2,2-二芳基醇。对 29 个偕二氧杂唑啉（BiOx）和偕二咪唑啉（BiIm）配体进行多元线性回归（MVLR）分析表明，对映选择性与配体的电子性质相关，具有更多供电子配体的配体提供更高的对映体过量值。进行了实验和计算的机理研究，支持了这样的假设，即还原消除是对映体决定的，配体的电子性质通过改变过渡态结构在反应坐标上的位置来影响对映选择性。这项研究证明了利用统计模型作为理解机理的平台的好处，并为立体协同镍和镍/光氧化还原交叉偶联中新兴的一类手性配体提供了新的见解。
