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Cyclic (Amino)(aryl)carbenes (CAArCs) as Strong σ‐Donating and π‐Accepting Ligands for Transition Metals
Author(s) -
Rao Bin,
Tang Huarong,
Zeng Xiaoming,
Liu Liu Leo,
Melaimi Mohand,
Bertrand Guy
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201507844
Subject(s) - chemistry , aryl , carbene , substituent , alkyl , deprotonation , rhodium , medicinal chemistry , nucleophile , transition metal , electrophile , cycloaddition , singlet state , catalysis , aniline , polymer chemistry , combinatorial chemistry , photochemistry , organic chemistry , ion , physics , nuclear physics , excited state
Cyclic (amino)(aryl)carbenes (CAArCs) result from the replacement of the alkyl substituent of cyclic (alkyl)(amino) carbenes (CAACs) by an aryl group. This structural modification leads to enhanced electrophilicity of the carbene center with retention of the high nucleophilicity of CAACs, and therefore CAArCs feature a small singlet–triplet gap. The isoindolium precursors are readily prepared in good yields, and deprotonation at low temperature, in the presence of [RhCl(cod)] 2 and [(Me 2 S)AuCl] lead to air‐stable rhodium and gold CAArC‐supported complexes, respectively. The rhodium complexes promote the [3+2] cycloaddition of diphenylcyclopropenone with ethyl phenylpropiolate, and induce the addition of 2‐vinylpyridine to alkenes by CH activation. The gold complexes allow for the catalytic three‐component preparation of 1,2‐dihydroquinolines from aniline and phenyl acetylene. These preliminary results illustrate the potential of CAArC ligands in transition‐metal catalysis.