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Mechanistic Investigation into Rh III ‐Catalyzed Intramolecular Redox‐Neutral Annulation of Aryl Hydrazines with a Tethered Alkyne
Author(s) -
Wu Weirong,
Ren Dongcheng,
Xu Benzhen,
Ma Xiaoying,
Huang Caiyun,
Zhang Jing,
Liu Tao
Publication year - 2017
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201700469
Subject(s) - chemistry , reductive elimination , intramolecular force , annulation , alkyne , catalysis , catalytic cycle , aryl , redox , medicinal chemistry , density functional theory , bond cleavage , computational chemistry , stereochemistry , organic chemistry , alkyl
A mechanistic study of the Cp*Rh III ‐catalyzed (Cp*=η 5 ‐pentamethylcyclopentadienyl) intramolecular redox‐neutral annulation of tethered alkynes was carried out by density functional calculations using the M06 method. Our results show that the reductive elimination step of the catalytic cycle is rate determining, and the overall energy barrier of the entire process is 31.4 kcal mol −1 ( L‐II → L‐TS8 ‐ 9 ). This is in agreement with experimental results that reported the C−H bond cleavage not to be the rate‐determining step. According to our calculations, the feasible mechanism for the Rh III →Rh V →Rh III process involves an acylamino migration and subsequent reductive elimination process, which is different from the pathway previously proposed by Li's group. The present calculations elucidate the experimental observations on the molecular level.