Hydrogen Bond-Accelerated meta-Selective C–H Borylation of Aromatic Compounds and Expression of Functional Group and Substrate Specificities

Abstract

We found that meta-selective C–H borylation of aromatic compounds was accelerated when using urea moiety-containing bipyridine-type ligands unlike in cases involving a bipyridine-type ligand without the urea moiety. The acceleration was due to the recognition and capture of the aromatic substrates by the urea moiety of the ligand by hydrogen bonding. The acceleration was further enhanced by modifying the electronic and steric properties of the ligand. The functional group and substrate specificities were also observed using the urea moiety-containing ligands.

Urea Derivatives as Functional Molecules: Supramolecular Capsules, Supramolecular Polymers, Supramolecular Gels, Artificial Hosts, and Catalysts

“…Kuninobu and Kanai et al reported the meta-selective borylation of aromatic amide compounds using iridium catalysts (Scheme 6). [164,165] Detailed studies on the reaction mechanism were performed based on discrete Fourier transform (DFT) calculations. [166] The key for this reactiont op roceed meta selectively is the molecular design of ligand 39,t he structure of which has ab ipyridyl site to coordinate iridium and au reido moietyt of orm ah ydrogen bondedc omplex.…”

An Introductory Overview of C–H Bond Activation/ Functionalization Chemistry with Focus on Catalytic C(sp3)–H Bond Borylation

“…For example, the strategy can target C(sp 3 )-H bonds in cyclopropanes (Shi et al, 2019) and cyclobutanes , -C(sp 3 )-H bonds of azacycles (Chen, Yang et al, 2020), and unbiased methylene C-H bonds of acyclic amides (Yang et al, 2021) giving the corresponding boronates with excellent enantioselectivities. Remote C(sp 3 )-H bond functionalization chemistry (Qiu and Wu, 2015;Sharma, 2018) has progressed slowly compared to the activation and subsequent transformation of remote C(sp 2 )-H bonds (see: Ali and Siddiqui, 2021;Genov et al, 2020;Lu et al, 2019;Kuninobu et al, 2015). In particular, asymmetric functionalization of remote C(sp 3 )-H bonds in easily accessible organic molecules remains underdeveloped, presumably due to the entropic penalty for the formation of larger-membered metallacycles via C-H metalation (Zhang and Shi, 2021).…”

Advances on Directing-Group Assisted meta-C-H Functionalization Catalyzed by Transition Metal

“…Yu 课题组 [48] [58] . Sunoj 等 [59] Phipps 课题组 [62] 借助离子对相互作用实现了芳香 季铵盐苯环间位硼化反应, 该反应中底物是含有正电荷 的季铵盐, 配体则含有磺酸根负离子, 磺酸根与季铵盐 相互作用, 使催化剂 Ir 接近苯环间位碳氢, 从而得到间 位硼化产物(Scheme 13).…”