Nucleophilic trifluormethylation of aryl boronic acid under heterogeneous Cu(INA)2 catalysis at room temperature: The catalytic copper-based protocol

• Published in: Molecular catalysis 2017-07, Vol.436, p.60-66
• Main Authors: Nguyen, Tu V., Ong, Toan D., Lam, Anh H.M., Pham, Vu. T., Phan, Nam T.S., Truong, Thanh
• Format: Article
• Language: English
• Subjects: Boronic acids; Cu(INA)2; Heterogeneous catalyst; TMSCF3; Trifluoromethylation
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2017.04.010

[Display omitted] •Cu(INA)2-catalyzed trifluoromethylation of aryl boronic acids.•First catalytic copper system for nucleophilic trifluoromethylation. Herein, we described the first heterogeneous and catalytic protocol for nucleophilic trifluoromethylation of aryl boronic acids. In particular, the synthesized metal-organic framework copper isonicotinate Cu(INA) 2 [INA=1,4-(NC5H4CO2)] exhibited exceptional catalytic activity toward the trifluoromethylation of boronic acids. Optimal conditions involve the use of Cu(INA)2 catalyst (30% mol), nucleophilic trifluoromethyltrimethylsilane (TMSCF3) and CsF reagent in 1,2-dichloroethane (DCE) solvent at room temperature in 2h. Molecular oxygen was employed as teminal oxidant. Noteworthily, reported conditions for same reactions required stoichiometric amount of homogeneous copper salts. Additionally, preliminary investigation of structure/activity relationship supported that weak interaction between copper centers and the presence of free carboxylate oxygen atoms within the network structure favored the trifluoromethylation. Subsequently, Cu(INA) 2 possessed higher activity than other copper-based homogeneous/heterogeneous catalysts and other MOFs catalysts. Leaching tests confirmed the heterogeneity of Cu(INA)2 during reaction. Thus, almost similar reaction yield was still obtained at 6th run.