Phang Yee Lin, Jin Ji-Kang, Zhang Feng-Lian, Wang Yi-Feng
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
Chem Commun (Camb). 2024 Apr 16;60(32):4275-4289. doi: 10.1039/d4cc00398e.
Organoboron compounds demonstrate diverse applications in the fields of organic synthesis, materials science, and medicinal chemistry. Compared to the conventional hydroboration reaction, radical hydroboration serves as an alternative approach for the synthesis of organoborons different mechanisms. In radical hydroboration, a boryl radical is initially generated from homolytic cleavage of a B-H or a B-B bond, which is then added to an unsaturated double bond to deliver a carbon radical. Subsequent hydrogen atom transfer or reduction of the carbon radical to form a carbanion followed by protonation gave the final product. Over the past few years, numerous efforts have been made for efficient synthesis of boryl radicals and the expansion of substrate scope of the radical hydroboration reaction. Here, we discuss the recent advancement of radical hydroboration and its associated mechanisms. Numerous radical hydroboration strategies employing N-heterocyclic carbene borane, bis(pinacolato)diboron and pinacolborane as the boron source were illustrated. Thermochemical, photochemical and electrochemical strategies for the generation of boryl radicals were also discussed in detail.
有机硼化合物在有机合成、材料科学和药物化学领域有着广泛的应用。与传统的硼氢化反应相比，自由基硼氢化反应作为一种合成有机硼化合物的替代方法，具有不同的反应机制。在自由基硼氢化反应中，硼自由基最初是由B-H或B-B键的均裂产生的，然后它会加成到不饱和双键上生成碳自由基。随后，碳自由基通过氢原子转移或还原形成碳负离子，再经质子化得到最终产物。在过去的几年里，人们为高效合成硼自由基和扩大自由基硼氢化反应的底物范围做出了许多努力。在此，我们讨论自由基硼氢化反应的最新进展及其相关机制。文中阐述了许多以氮杂环卡宾硼烷、双(频哪醇合)二硼和频哪醇硼烷为硼源的自由基硼氢化策略。还详细讨论了生成硼自由基的热化学、光化学和电化学策略。
