Monoalkylation of aniline with trichloroacetimidate catalyzed by (±)-camphorsulfonic acid through an S1 reaction based on dual hydrogen-bonding activation modes

• Published in: New journal of chemistry Vol. 44; no. 14; pp. 5526 - 5534
• Main Authors: Lu, Ka, Dai, Yang, Yan, Chao-Xian, Yang, Fang-Ling, Yang, Xing, Zhou, Pan-Pan, Yang, Zhaoyong
• Format: Journal Article
• Language: English
• Published: 06.04.2020
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d0nj00239a

Monoalkylation of aniline can be readily achieved using trichloroacetimidate as an alkylating agent and a Brønsted acid, such as (±)-camphorsulfonic acid, as a catalyst. In this study, systematic theoretical calculations were performed to understand the reaction mechanism for the monoalkylation of 2,5-dichloroaniline with trichloroacetimidate catalyzed by (±)-camphorsulfonic acid; moreover, the judgement about whether the reaction takes place via an S N 1 or S N 2 mechanism was elaborated. The two possible proton-transfer reaction mechanisms proposed herein based on the experimental results were investigated; moreover, another two possible reaction mechanisms involving the activation of both 2,5-dichloroaniline and trichloroacetimidate by (±)-camphorsulfonic acid via dual hydrogen-bonding activation modes were evaluated. The calculated results suggest that the reaction between 2,5-dichloroaniline and trichloroacetimidate catalyzed by (±)-camphorsulfonic acid preferentially occurs through the S N 1 mechanism based on the dual hydrogen-bonding activation modes. Herein, the monoalkylation of anilines with trichloroacetimidates catalyzed by CSA was investigated theoretically, and it was found that the reaction occurred through an S N 1 reaction involving the dual hydrogen-bonding activation modes.