A nickel-catalyzed cycloaddition of aromatic (O-benzyl)ketoximes with alkynes to afford 3,4-disubstituted isoquinoline derivatives has been developed. The reaction involves oxidative addition of N–O bond of O-benzylketoxime to Ni(0) and subsequent intermolecular C–H bond activation via elimination of benzyl alcohol. It was also found that ketoximes participate in the nickel-catalyzed reaction with alkynes to furnish isoquinoline N-oxide derivatives.
(Pentamethylcyclopentadienyl)cobalt(III)-Catalyzed Oxidative [4+2] Annulation of NH Imines with Alkynes: Straightforward Synthesis of Multisubstituted Isoquinolines
作者:Shang-Shi Zhang、Xu-Ge Liu、Shi-Yong Chen、Dong-Hang Tan、Chun-Yong Jiang、Jia-Qiang Wu、Qingjiang Li、Honggen Wang
DOI:10.1002/adsc.201600025
日期:2016.5.19
A synthetic method for isoquinoline synthesis via a [4+2] annulation of NH imines with alkynes using the high‐valent (pentamethylcyclopentadienyl)cobalt(III) [Cp*Co(III)] catalyst is described. Cerium(IV) sulfate was found to be an efficient oxidant in lieu of the commonly used copper or silver salts. Broad substrate scope, high functional group tolerance, and generally good yields were observed.