Premium
Cp*Rh III ‐Catalyzed Sterically Controlled C(sp 3 )−H Selective Mono‐ and Diarylation of 8‐Methylquinolines with Organoborons **
Author(s) -
Kumar Rakesh,
Parmar Diksha,
Gupta Shiv Shankar,
Chandra Devesh,
Dhiman Ankit Kumar,
Sharma Upendra
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201905591
Subject(s) - catalysis , steric effects , chemistry , medicinal chemistry , stereochemistry , organic chemistry
Herein, the Rh III ‐catalyzed selective monoarylation and diarylation (symmetrical and unsymmetrical) of 8‐methylquinolines with organoboron reagents are disclosed. The selective monoarylation of primary C(sp 3 )−H bonds is achieved by using 7‐substituted 8‐methylquinolines or by changing the quantity of the aryl boronic acids. The method is also applicable for the arylation of 2‐ethylpyridines, and the heteroarylation with thiophene‐2‐ylboronic acids. Symmetrical and unsymmetrical diarylation of 8‐methylquinolines have been carried out in one‐pot and sequential manner, respectively. Late‐stage monoarylation of oxime derivatives and gram‐scale synthesis of monoarylated products has also been carried out. A mechanistic study revealed that the current reaction is first order with respect to both reactants and a five‐membered rhodacycle intermediate may be involved in the catalytic cycle.