华东师范大学洪恺团队报道了通过二硼自由基的钯催化碘硼化合物的级联Heck偶联及硼化反应。相关研究成果发表在2024年3月6日出版的《德国应用化学》。

双硼酸盐是有机化学中多用途的合成材料。然而，在之前的报告中，它们主要作为亲核试剂，这一事实限制了它们的合成潜力。

该文中，研究人员公开了α-卤代双代双硼酸盐的两亲反应性，其中第一次催化利用是通过将正式的Heck交叉偶联，与醛或亚胺的高度非对映选择性烯丙基硼化合并来实现的，为快速组装多官能化含硼化合物提供了新的途径。

研究人员证明了这种级联反应是高效的，并且与各种官能团和广泛的杂环相容。与经典的Pd（0/II）场景相反，机理实验和DFT计算为涉及Pd（I）/二硼基碳自由基中间体的催化循环提供了有力的证据。

附：英文原文

Title: Palladium-Catalyzed Cascade Heck Coupling and Allylboration of Iododiboron Compounds via Diboryl Radicals

Author: Yi Wei, Xiao-Yu Xie, Jiabin Liu, Xiaoxiao Liu, Bo Zhang, Xin-Yi Chen, Shi-Jun Li, Yu Lan, Kai Hong

Issue&Volume: 2024-03-06

Abstract: Geminal bis(boronates) are versatile synthetic building blocks in organic chemistry. The fact that they predominantly serve as nucleophiles in the previous reports, however, has restrained their synthetic potential. Herein we disclose the ambiphilic reactivity of α-halogenated geminal bis(boronates), of which the first catalytic utilization was accomplished by merging a formal Heck cross-coupling with a highly diastereoselective allylboration of aldehydes or imines, providing a new avenue for rapid assembly of polyfunctionalized boron-containing compounds. We demonstrated that this cascade reaction is highly efficient and compatible with various functional groups, and a wide range of heterocycles. In contrast to a classical Pd(0/II) scenario, mechanistic experiments and DFT calculations have provided strong evidence for a catalytic cycle involving Pd(I)/diboryl carbon radical intermediates.

DOI: 10.1002/anie.202401050

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202401050