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Manganese‐Catalyzed Dehydrogenative [4+2] Annulation of NH Imines and Alkynes by CH/NH Activation
Author(s) -
He Ruoyu,
Huang ZhiTang,
Zheng QiYu,
Wang Congyang
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201402575
Subject(s) - manganese , catalysis , chemistry , annulation , isoquinoline , catalytic cycle , stoichiometry , hydride , dehydrogenation , medicinal chemistry , transition metal , redox , combinatorial chemistry , metal , photochemistry , organic chemistry
Described herein is a manganese‐catalyzed dehydrogenative [4+2] annulation of NH imines and alkynes, a reaction providing highly atom‐economical access to diverse isoquinolines. This transformation represents the first example of manganese‐catalyzed CH activation of imines; the stoichiometric variant of the cyclomanganation was reported in 1971. The redox neutral reaction produces H 2 as the major byproduct and eliminates the need for any oxidants, external ligands, or additives, thus standing out from known isoquinoline synthesis by transition‐metal‐catalyzed CH activation. Mechanistic studies revealed the five‐membered manganacycle and manganese hydride species as key reaction intermediates in the catalytic cycle.