Enantioselective metallaphotoredox catalysis, which combines photoredox catalysis and asymmetric transition-metal catalysis, has become an effective approach to achieve stereoconvergence under mild conditions. Although many impressive synthetic approaches have been developed to access central chirality, the construction of axial chirality by metallaphotoredox catalysis still remains underexplored. Herein
结合了光氧化还原催化和不对称过渡金属催化的对映选择性金属光氧化还原催化已成为在温和条件下实现立体收敛的有效途径。尽管已经开发了许多令人印象深刻的合成方法来获得中心手性,但通过金属光氧化还原催化构建轴向手性仍未得到充分探索。在此,我们报告了两种可见光诱导的钴催化的联芳基二醛不对称还原偶联合成轴向手性醛(60 个例子,高达 98% 的产率,>19:1 dr 和 >99% ee)。该方案显示出良好的官能团耐受性、广泛的底物范围以及出色的非对映和对映选择性。
Visible <scp>Light‐Mediated</scp> Cobalt and Photoredox <scp>Dual‐Catalyzed</scp> Asymmetric Reductive Coupling for Axially Chiral Secondary Alcohols<sup>†</sup>
Secondary alcohols bearing both axial and central chirality comprise attractive biological activity and exhibit excellent chiral induction in asymmetric reactions. However, only very limited asymmetric catalytic approaches were developed for their synthesis. We herein describe visible light-mediated cobalt-catalyzed asymmetric reductive Grignard-type addition of aryl iodides with axially prochiral biaryl
Catalytic Atroposelective Aerobic Oxidation Approaches to Axially Chiral Molecules
作者:Lenin Kumar Verdhi、Asit Ghosh、Natalia Fridman、Alex M. Szpilman
DOI:10.1021/acs.joc.3c00417
日期:2023.7.7
copper and chiral nitroxide co-catalyzed aerobic enantioselective oxidation process has been developed that allows access to axially chiral molecules. Two complementary atroposelective approaches, oxidative kinetic resolution (OKR) and desymmetrization, were studied using ambient air as the stoichiometric terminal oxidant. OKR of rac-N-arylpyrrole alcohols and rac-biaryl alcohols affords the optically
Herein we present an efficient chiral phosphoric-acid-catalyzed atropoenantioselective asymmetric reductive amination of biaryl dialdehydes. The process involves desymmetrization and the following kinetic resolution, with a wide range of axially chiral aryl aldehydes obtained with high optical purities.