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Rh III ‐Catalyzed C(sp 3 )H Bond Activation by an External Base Metalation/Deprotonation Mechanism: A Theoretical Study
Author(s) -
Jiang Julong,
Ramozzi Romain,
Morokuma Keiji
Publication year - 2015
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.201501539
Subject(s) - metalation , deprotonation , chemistry , catalytic cycle , intramolecular force , metathesis , cationic polymerization , catalysis , copper , medicinal chemistry , density functional theory , base (topology) , stereochemistry , photochemistry , computational chemistry , polymer chemistry , organic chemistry , ion , polymer , polymerization , mathematical analysis , mathematics
The C(sp 3 )H bond activation of 8‐methylquinoline followed by alkyne insertion catalyzed by a Rh III complex has been studied by using density functional theory (DFT) calculations. Contrary to common belief, the CH bond activation of methylquinoline does not occur by the traditional intramolecular concerted metalation/deprotonation (CMD) mechanism but by an external base CMD mechanism. The use of free acetate or copper(II) acetate as base permits the CH activation step, as observed experimentally. However, the following insertion is possible only if copper(II) acetate is used. The insertion followed by metathesis occurs via a cationic Rh III complex and is irreversible, which ensures the efficiency of the entire process. Therefore the use of copper is crucial for completing the catalytic cycle. The present work should help to rationalize the origins of the experimental results described in the literature.