Highly Active Palladium‐Based Catalyst System for the Aerobic Oxidative Direct Coupling of Benzene to Biphenyl. Issue 2 (13th November 2015)

• Record Type: Journal Article
• Authors: Liu, Yangqing; Wang, Xiaochen; Cai, Xiaochun; Chen, Guojian; Li, Jing; Zhou, Yu; Wang, Jun
• Is Part Of: ChemCatChem. Volume 8:Issue 2(2016)
• Page Start: 448
• Page End: 454
• Publication Date: 2015-11-13
• Subjects: acidity -- C−C coupling -- dimerization -- oxidation -- palladium; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201500951
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: A highly efficient Pd‐containing catalytic system for the intermolecular direct C−H homocoupling of benzene to biphenyl has been developed. The catalytic system was composed of Pd(OAc)2 with trifluoromethanesulfonic acid (TfOH) as an additive and O2 as the sole oxygen source in the absence of any metal‐containing cocatalyst. An excellent efficiency of Pd II with the acidic additive was attained in the aerobic oxidation of benzene to biphenyl. A high yield (25.3 %) and selectivity (98 %) were achieved by using a small amount of Pd(OAc)2 (0.07 mol %) and TfOH, which gave a high turnover number (180) for Pd species. Theoretical calculation by DFT and UV/Vis absorption spectra illustrated that the formation of electropositive Pd II species in the presence of TfOH contributed to the high efficiency of the catalytic system. Abstract : The acids have it : A highly efficient Pd‐based catalytic system is constructed for the direct oxidative coupling of benzene with dioxygen to biphenyl with the C−H activation strategy. The system exhibits an extremely high turnover number of 180, which is accomplished with the aid of CF3 SO3 H without a metal‐bearing cocatalyst.