American Chemical Society
jo8b00711_si_001.pdf (14.3 MB)

Impact of the Valence Charge of Transition Metals on the Cobalt- and Rhodium-Catalyzed Synthesis of Indenamines, Indenols, and Isoquinolinium Salts: A Catalytic Cycle Involving MIII/MV [M = Co, Rh] for [4 + 2] Annulation

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journal contribution
posted on 2018-06-13, 00:00 authored by Mong-Feng Chiou, Jayachandran Jayakumar, Chien-Hong Cheng, Shih-Ching Chuang
Reaction mechanisms for the synthesis of indenamines, indenols, and isoquinolinium salts through cobalt- and rhodium-catalysis were investigated using density functional theory calculations. We found that the valence charge of transition metals dramatically influences the reaction pathways. Catalytic reactions involving lower-oxidation-state transition metals (MI/MIII, M = Co and Rh) generally favor a [3 + 2] cyclization pathway, whereas those involving higher oxidation states (MIII/MV) proceed through a [4 + 2] cyclization pathway. A catalytic cycle with novel MIII/MV as a crucial species was successfully revealed for isoquinolinium salts synthesis, in which highly valent MV was encountered not only in the [RhCp*]-catalysis but also in the [CoCp*]-catalysis.