BF3⋅Et2O‐catalyzed C2‐selective C−H borylation of indoles with bis(pinacolato)diboron was developed to afford indole‐2‐boronicacid pinacol esters. A variety of functional groups were tolerated, and other heteroarenes like pyrrole and benzo[b]thiophene were also suitable substrates. An electrophilic substitution mechanism was proposed based on the preliminary mechanisticstudies. This novel transformation utilizes
Benzoic Acid-Promoted C2–H Borylation of Indoles with Pinacolborane
作者:Youliang Zou、Binfeng Zhang、Li Wang、Hua Zhang
DOI:10.1021/acs.orglett.1c00809
日期:2021.4.2
A benzoic acid-promoted C2–H borylation of indoles with pinacolborane to afford C2-borylated indoles is developed. Preliminary mechanistic studies indicate BH3-related borane species formed via the decomposition of pinacolborane to be the probable catalyst. This transformation provides a prompt route toward the synthesis of diverse C2-functionalized indoles.
Selective carbon–carbon bond activation is important in chemical industry and fundamental organic synthesis, but remains challenging. In this study, non-polar unstrained Csp2–Csp3 and Csp2–Csp2 bond activation was achieved by B(OMe)3/B2pin2-mediated fragmentation borylation. Various indole derivatives underwent C2-regioselective C–C bond activation to afford two C–B bonds under transition-metal-free
C–H Functionalization at Sterically Congested Positions by the Platinum-Catalyzed Borylation of Arenes
作者:Takayuki Furukawa、Mamoru Tobisu、Naoto Chatani
DOI:10.1021/jacs.5b07677
日期:2015.9.30
Despite significant progress in the area of C-H bond functionalization of arenes, no general method has been reported for the functionalization of C-H bonds at the sterically encumbered positions of simple arenes, such as mesitylene. Herein, we report the development of the first platinum-based catalyst for C-H borylation of arenes and heteroarenes. Notably, this method exhibited high tolerance toward steric hindrance and provided rapid access to a series of 2,6-disubstituted phenylboronic esters, valuable building blocks for further elaborations.