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Regioselective Base‐controlled Pd‐catalyzed Arylation of Imidazo[1,2‐a]pyridines: leading selectivity at C8 position by N‐chelation over O‐chelation
Author(s) -
Tali Javeed Ahmad,
Singh Davinder,
Kumar Gulshan,
Shankar Ravi
Publication year - 2021
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202100225
Subject(s) - chemistry , chelation , catalysis , regioselectivity , pyridine , aryl , combinatorial chemistry , substrate (aquarium) , selectivity , base (topology) , yield (engineering) , medicinal chemistry , organic chemistry , mathematical analysis , alkyl , oceanography , mathematics , geology , materials science , metallurgy
A base controlled operationally simple catalytic system for the regioselective arylation of 2‐aryl‐imidazo[1,2‐ a ]pyridine by Pd catalyzed C−H activation has been developed. Herein, we report Pd/Ag 2 CO 3 promoted C8 arylation of the heterocycles by overriding the N‐chelation on O‐chelation. In this way, various examples have been synthesized in good to excellent yield. Furthermore, Pd/ t ‐BuOK system has been developed for the novel deformylative C3 arylation of 2‐aryl‐imidazo[1,2‐ a ]pyridine. The choice of the catalytic system is also demonstrated for heteroarylation. Both standardized protocols have been explored with broad substrate scope and good functional group tolerance.