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N−H Imine as a Powerful Directing Group for Cobalt‐Catalyzed Olefin Hydroarylation
Author(s) -
Xu Wengang,
Yoshikai Naohiko
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201605877
Subject(s) - imine , chemistry , aryl , steric effects , cobalt , catalysis , alkyl , olefin fiber , alkylation , rhodium , condensation reaction , medicinal chemistry , organic chemistry , polymer chemistry , combinatorial chemistry
N‐alkyl and N‐aryl imines have been frequently used as directing groups in rhodium‐ and cobalt‐catalyzed hydroarylation reactions of olefins and alkynes. However, the scope of such hydroarylation reactions has been limited by the difficulty of preparation of sterically hindered imines by condensation, and also by the steric bulkiness of the imine group itself. Reported herein is that an N−H imine serves as an alternative and highly effective directing group for cobalt‐catalyzed hydroarylation of olefins, and unlocks many of the limitations associated with the previously employed N‐aryl imine directing group. The power of this minimal nitrogen directing group is manifested in a fourfold ortho alkylation of benzophenone imine, and it occurs rapidly at ambient temperature.