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Switching of Regioselectivity in a Perfluorohexyl Iodide Mediated Synthesis of Phenylimidazo[1,2‐ a ]pyridines
Author(s) -
Roslan Irwan Iskandar,
Chuah GaikKhuan,
Jaenicke Stephan
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201601586
Subject(s) - regioselectivity , chemistry , iodide , electrophile , halogenation , alkyne , ring (chemistry) , stereochemistry , combinatorial chemistry , medicinal chemistry , organic chemistry , catalysis
3‐Phenylimidazo[1,2‐ a ]pyridines were synthesized through the perfluorohexyl iodide mediated coupling of 2‐aminopyridines and phenylacetylenes. In situ iodination of the terminal alkyne by perfluorohexyl iodide reverses the polarity by generating a transient electrophilic iodoalkyne, and this alters the regioselectivity of the phenyl group. The reaction then proceeds by tandem electrophilic alkynylation and cyclization to form the fused‐ring product. The protocol affords the 3‐phenyl isomer with full regioselectivity and is complementary to reported methodologies for the synthesis of the 2‐phenyl isomer starting from the same substrates.