近日，香港科技大学全杨健团队实现了通过硼–碳中心双自由基合成稳定且具有环张力的硼杂环。相关论文于2025年4月23日发表在《自然-化学》杂志上。

硼环化合物是重要的功能性支架，与碳类似物相比，通常表现出优越或独特的性能。五元氧杂环是美国食品药品监督管理局批准的硼类药物中的关键药效团。同时，六元掺硼多环芳烃增强了分子材料的多样性和功能性。然而，由于制备方法有限，含硼四元环的研究较少。它们固有的环应变使它们的合成在热力学上不利，并阻碍了对其性质和应用的探索。

研究组报告了一种三重态能量转移催化，通过硼-碳中心二自由基的分子内偶联来制造空气稳定的苯并硼烯。此外，通过调节底物π共轭结构和激发能，以硼-碳为中心的二自由基可以进行正式的1,6-和1,5-环化，分别产生二氢硼化物和二氢环丙醇衍生物。无金属的中性反应条件确保了广泛的反应范围，从而产生结构多样的硼环，这些硼环足够稳定，可以通过柱色谱法纯化。对硼烷环的进一步改性实现了能够容易地合成具有独特光电性能的氧硼烷环和二氢硼化物稠合多环芳烃。

附：英文原文

Title: Synthesis of strained, air-stable boracycles via boron–carbon-centred diradicals

Author: Wang, Xinmou, Zhang, Peiqi, Yang, Zhiyi, Sun, Weixuan, Lyu, Hairong, Lin, Zhenyang, Quan, Yangjian

Issue&Volume: 2025-04-23

Abstract: Boracycles are important functional scaffolds, often exhibiting superior or unique performance compared with their carbon analogues. Five-membered oxaboracycles are key pharmacophores in Food and Drug Administration-approved boron drugs. Meanwhile, six-membered boron-doped polycyclic aromatic hydrocarbons enhance the diversification and functionality of molecular materials. However, boron-containing four-membered rings are less studied owing to limited preparative approaches. Their inherent ring strain makes their synthesis thermodynamically unfavourable and hinders the exploration of their properties and applications. Here we report a triplet energy transfer catalysis for crafting air-stable benzoboretenes through intramolecular coupling of boron–carbon-centred diradicals. In addition, by modulating substrate π-conjugation structures and excitation energies, boron–carbon-centred diradicals can undergo formal 1,6- and 1,5-cyclization to deliver dihydroborinine and dihydrocyclopropaborole derivatives, respectively. The metal-free neutral reaction conditions ensure a broad reaction scope, resulting in structurally diverse boracycles that are stable enough to be purified via column chromatography. Further modification of the boracycles enables the facile synthesis of oxaborabicycles and dihydroborinine-fused polycyclic aromatic hydrocarbons with unique optoelectronic properties.

DOI: 10.1038/s41557-025-01807-x

Source: https://www.nature.com/articles/s41557-025-01807-x