Wang Rui, Wang Cheng-Yu, Liu Peng, Bian Kang-Jie, Yang Chi, Wu Bing-Bing, Wang Xi-Sheng
Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, P. R. China.
State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
Sci Adv. 2023 Sep;9(35):eadh5195. doi: 10.1126/sciadv.adh5195. Epub 2023 Sep 1.
Empowered by the ubiquity of carbonyl functional groups in organic compounds, decarbonylative functionalization was prevalent in the construction of complex molecules. Under this context, asymmetric decarbonylative functionalization has emerged as an efficient pathway to accessing chiral motifs. However, ablation of enantiomeric control in a conventional 2e transition metal-catalyzed process was notable because of harsh conditions (high temperatures, etc.) that are usually required. To address this challenge and use readily accessible aldehyde directly, we report the asymmetric radical decarbonylative azidation and cyanation. Diverse aldehydes were directly used as alkyl radical precursor, engaging in the subsequent inner-sphere or outer-sphere ligand transfer where functional motifs (CN and N) could be incorporated in excellent site- and enantioselectivity. Mild conditions, broad scope, excellent regioselectivity (driven by polarity-matching strategy), and enantioselectivity were shown for both transformations. This radical decarbonylative strategy using aldehydes as alkyl radical precursor has offered a powerful reaction manifold in asymmetric radical transformations to construct functional motifs regio- and stereoselectively.
受有机化合物中羰基官能团普遍存在的推动,脱羰基官能化在复杂分子的构建中很常见。在此背景下,不对称脱羰基官能化已成为获得手性基序的有效途径。然而,在传统的2e过渡金属催化过程中,对映体控制的缺失很明显,因为通常需要苛刻的条件(高温等)。为了应对这一挑战并直接使用易于获得的醛,我们报道了不对称自由基脱羰基叠氮化和氰化反应。多种醛被直接用作烷基自由基前体,参与随后的内球或外球配体转移,其中官能团(CN和N)可以以优异的位点选择性和对映选择性引入。两种转化反应均表现出温和的条件、广泛的底物范围、优异的区域选择性(由极性匹配策略驱动)和对映选择性。这种以醛为烷基自由基前体的自由基脱羰基策略在不对称自由基转化中提供了一个强大的反应体系,能够区域和立体选择性地构建官能团。