Lewis Acid Catalyzed Ring‐Opening Reaction of Cyclobutanones towards Conjugated Enones
作者:Min Zhang、Jiqiang Gao、Jinbo Zhao、Tingtian Qiu、Zhongjuan Li、Ziteng Guo、Chunhui Liu、Yu Liu
DOI:10.1002/ejoc.202101335
日期:2021.12.7
An unprecedented Fe-catalyzed ring-opening reaction of simple cyclobutanones was disclosed. Such a novel approach givesaccess to substituted conjugate enones with good functional group tolerance in high yields under mild conditions.
Iminium salts are generated in situ, react with TiCl4-trialkylamines, and diaryl ketones to produce 3,3-diaryl-cyclobutanones in moderate to good yields.
Simple and Efficient Methods of Synthesis of 3,3-Diarylcyclobutanone and 3,3-Diarylcyclobutylamine Derivatives Using the TiCl<sub>4</sub>/R<sub>3</sub>N Reagent System
The iminium ions generated in situ by the oxidation of NN-diisopropyl-N-benzylamine using iodine react with diaryl ketones in the presence of TiCl4/R3N to give the corresponding 3,3-diarylcyclobutanones in moderate to good yields (49-86%). The 3,3-diarylcyclobutanone iminium ions formed in this transformation was reduced in situ with B2H6 to produce the corresponding 3,3diarylcyclobutylamines (52-79% yields), a class of compounds with potential antidepressant activity. In addition, a series of NN-dimethyl-3,3-diarylcyclobutylamines were synthesized by the reductive amination of the corresponding 3,3-diarylcyclobutanone derivatives.