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Ruthenium‐Catalyzed Oxidative Coupling/Cyclization of Isoquinolones with Alkynes through CH/NH Activation: Mechanism Study and Synthesis of Dibenzo[ a , g ]quinolizin‐8‐one Derivatives
Author(s) -
Li Bin,
Feng Huiliang,
Wang Nuancheng,
Ma Jianfeng,
Song Haibin,
Xu Shansheng,
Wang Baiquan
Publication year - 2012
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.201201862
Subject(s) - chemistry , alkyne , catalysis , oxidative coupling of methane , ruthenium , oxidative phosphorylation , medicinal chemistry , stereochemistry , combinatorial chemistry , oxidative addition , photochemistry , organic chemistry , biochemistry
The mechanism of [{RuCl 2 ( p ‐cymene)} 2 ]‐catalyzed oxidative annulations of isoquinolones with alkynes was investigated in detail. The first step is an acetate‐assisted CH bond activation process to form cyclometalated compounds. Subsequent mono‐alkyne insertion of the RuC bonds of the cyclometalated compounds then takes place. Finally, oxidative coupling of the CN bond of the insertion compounds occurs to afford Ru 0 sandwich complexes that undergo oxidation to regenerate the catalytically active Ru II complex with the copper oxidant and release the desired dibenzo[ a , g ]quinolizin‐8‐one derivatives. All of the relevant intermediates were fully characterized and determined by single crystal X‐ray diffraction analysis. The [{RuCl 2 ( p ‐cymene)} 2 ]‐catalyzed CH bond functionalization of isoquinolones with alkynes to synthesize dibenzo[ a , g ]quinolizin‐8‐one derivatives through CH/NH activation was also demonstrated.