山东大学张永强团队报道了(串联)钛催化的不对称氢原子转移还原环氧化物。相关研究成果于2022年10月20日发表在《德国应用化学》。

不对称氢原子转移（HAT）可以说是获得重要手性叔碳中心最直接的途径之一，然而，这仍然是一个长期的挑战。

该文报告了第一个基于顺序（salen）TiIII引发的自由基生成，和（salen）TiIV控制的对映选择性HAT过程催化配位诱导不对称HAT反应的例子。该反应以对映收敛的方式将容易获得的甘油酯、硫代酯和酰胺转化为合成有价值的甲醛醛缩合物，具有广泛的范围和高度的区域和对映选择性。

附：英文原文

Title: (Salen)Titanium-Catalyzed Asymmetric Hydrogen Atom Transfer for Epoxides Reduction

Author: Yongqiang Zhang, Zhongyun Xu, Jian Shen, Longfei Li, Wanjiao Chen, Shengxiao Li, Jie Jiang

Issue&Volume: 2022-10-20

Abstract: Asymmetric hydrogen atom transfer (HAT) represents arguably one of the most straightforward access to the significant chiral tertiary carbon centers, however, remains a long-standing challenge. Herein, the first example of catalytic coordination-induced asymmetric HAT reaction has been developed relying on a sequential (salen)TiIII-initiated radical generation and (salen)TiIV-controlled enantioselective HAT process. The reaction transforms easily accessible glycidic esters, thioesters and amides to synthetically valuable formal formaldehyde aldol adducts in an enantioconvergent manner, along with broad scope and highly regio- and enantioselectivities.

DOI: 10.1002/anie.202214111

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202214111