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Iron‐Carbonyl‐Catalyzed Redox‐Neutral [4+2] Annulation of N−H Imines and Internal Alkynes by C−H Bond Activation
Author(s) -
Jia Teng,
Zhao Chongyang,
He Ruoyu,
Chen Hui,
Wang Congyang
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201600365
Subject(s) - annulation , chemistry , catalysis , alkyne , ligand (biochemistry) , medicinal chemistry , redox , oxidative addition , stereochemistry , stoichiometry , photochemistry , organic chemistry , biochemistry , receptor
Stoichiometric C−H bond activation of arenes mediated by iron carbonyls was reported by Pauson as early as in 1965, yet the catalytic C−H transformations have not been developed. Herein, an iron‐catalyzed annulation of N−H imines and internal alkynes to furnish cis ‐3,4‐dihydroisoquinolines is described, and represents the first iron‐carbonyl‐catalyzed C−H activation reaction of arenes. Remarkablely, this is also the first redox‐neutral [4+2] annulation of imines and alkynes proceeding by C−H activation. The reaction also features only cis stereoselectivity and excellent atom economy as neither base, nor external ligand, nor additive is required. Experimental and theoretical studies reveal an oxidative addition mechanism for C−H bond activation to afford a dinuclear ferracycle and a synergetic diiron‐promoted H‐transfer to the alkyne as the turnover‐determining step.