Ju Guodong, Huang Zhibin, Zhao Yingsheng
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453000, China.
Nat Commun. 2024 Apr 2;15(1):2847. doi: 10.1038/s41467-024-47205-8.
An ideal approach for the construction of aryl boron compounds is to selectively replace a C-H bond in arenes with a C-B bond, and controlling regioselectivity is one of the most challenging aspects of these transformations. Herein, we report an iridium-catalyzed trialkoxysilane protecting group-assisted regioselective C-H borylation of arenes, including derivatives of benzaldehydes, acetophenones, benzoic acids, benzyl alcohols, phenols, aryl silanes, benzyl silanes, and multi-functionalized aromatic rings are all well tolerated and gave the para -selective C-H borylation products in a short time without the requirement of inert gases atmosphere. The site-selective C-H borylation can be adjustable by installing the developed trialkoxysilane protecting group on different functional groups on one aromatic ring. Importantly, the preparation process of the trialkoxychlorosilane is efficient and scalable. Mechanistic and computational studies reveal that the steric hindrance of the trialkoxysilane protecting group plays a key role in dictating the para-selectivity.
构建芳基硼化合物的理想方法是用C-B键选择性取代芳烃中的C-H键，而控制区域选择性是这些转化中最具挑战性的方面之一。在此，我们报道了一种铱催化的三烷氧基硅烷保护基辅助的芳烃区域选择性C-H硼化反应，包括苯甲醛、苯乙酮、苯甲酸、苄醇、苯酚、芳基硅烷、苄基硅烷的衍生物以及多官能化芳环都能很好地耐受，并且在不需要惰性气体气氛的情况下短时间内得到对位选择性C-H硼化产物。通过在一个芳环上的不同官能团上安装所开发的三烷氧基硅烷保护基，可以调节位点选择性C-H硼化反应。重要的是，三烷氧基氯硅烷的制备过程高效且可扩展。机理和计算研究表明，三烷氧基硅烷保护基的空间位阻在决定对位选择性方面起关键作用。
