Regioselectivity of Pd-catalyzed o-carboranearylation: a theoretical view  

作　　者：Jiying Liu Dongmin Fu Zitong Chen Tiantian Li Ling-Bo Qu Shi-Jun Li Wenjing Zhang Yu Lan 

机构地区：[1]Green Catalysis Center,and College of Chemistry,Zhengzhou University,Zhengzhou,Henan 450001,China [2]School of Chemistry and Chemical Engineering,and Chongqing Key Laboratory of Theoretical and Computational Chemistry,Chongqing University,Chongqing 400030,China

出　　处：《Organic Chemistry Frontiers》2022年第6期1686-1695,共10页有机化学前沿（英文）

基　　金：supported by the National Natural Science Foundation of China(Grants 21903071);the Program for Science Technology Innovation Talents in Universities of Henan Province(No.20HASTIT004).

摘　　要：The mechanism and the regioselectivity of Pd-catalyzed B(4)–H arylation and B(4,5)–H diarylation foro-carborane with bidentate directing groups were investigated. The complete catalytic cycle involves Pdmediated concerted metalation–deprotonation, oxidative addition, counterion exchange, and reductiveelimination, where counterion exchange is critical. The reductive elimination is the rate- and regioselectivity-determining step for the whole catalytic cycle. B(3)-Arylation is unfavorable because the stericrepulsion between the substituent group on C(2) and the metal moiety would lead to significant distortionof o-carborane and would result in a higher activation energy for reductive elimination. The distortion ofo-carborane can be clearly observed from the change of its aromaticity in the corresponding transitionstates by the calculation of nucleus-independent chemical shifts. Moreover, counterion exchange withcarboxylate before reductive elimination significantly increases the positive charge of palladium, whichleads to a lower activation free energy for the sequential step.

关 键 词：ELIMINATION CATALYZED REDUCTIVE 

分 类 号：O62[理学—有机化学]