Sun Wanqi, Jin Yujie, Wang Yongtao, Wen Zeyu, Sun Jizeng, Yao Jia, Duttwyler Simon, Li Haoran
Department of Chemistry, Zhejiang University 866 Yuhangtang Rd Hangzhou 310058 China
Center of Chemistry for Frontier Technologies, ZJU-NHU United R&D Center, Zhejiang University 866 Yuhangtang Rd Hangzhou 310058 China.
Chem Sci. 2025 Feb 26;16(14):5942-5947. doi: 10.1039/d5sc00234f. eCollection 2025 Apr 2.
Highly regioselective B(12) substitutions of the monocarborane anion [CBH] has been a challenge. Here, we synthesized a stable B-O-N zwitterionic compound with an impressive yield (isolated yield up to 98%) and excellent regioselectivity at the B(12) position under catalyst-free conditions. The kinetics, substituent effect, and capture experiments are paired with theoretical calculations, showing that the reaction mechanism is oxidation-induced nucleophilic substitution. The hydride anion at the B(12) position is abstracted by an oxoammonium oxidant with lower cleavage energy of 4.2 kcal mol than B(7-11) positions, thereby changing the electronegativity upon the conversion of [CBH] to neutral [CBH], in turn giving very high regioselectivity for nucleophilic substitution. This work presents an effective method for synthesizing B(12) oxygen derivatives of the [CBH] anion.
单碳硼烷阴离子[CBH]的高区域选择性硼（B12）取代一直是一个挑战。在此，我们合成了一种稳定的硼-氧-氮两性离子化合物，在无催化剂条件下，其产率令人印象深刻（分离产率高达98%），且在B（12）位具有出色的区域选择性。动力学、取代基效应和捕获实验与理论计算相结合，表明反应机理是氧化诱导的亲核取代。B（12）位的氢负离子被氧鎓氧化剂夺取，其裂解能（4.2 kcal mol）低于B（7-11）位，从而在[CBH]转化为中性[CBH]时改变了电负性，进而对亲核取代产生了非常高的区域选择性。这项工作提出了一种合成[CBH]阴离子B（12）氧衍生物的有效方法。
