Title: | The C-H activated controlled mono- and di-olefination of arenes in ionic liquids at room temperature |
Address: | "Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University Chengdu 610065 P. R. China. Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, West China School of Pharmacy, Sichuan University Chengdu 610041 P. R. China yaotian90@scu.edu.cn" |
ISSN/ISBN: | 2046-2069 (Electronic) 2046-2069 (Linking) |
Abstract: | "In this study, controlled mono and di-olefination of arenes was first realized at room temperature via the C-H bond activation in ionic liquids, probably due to the positive effects of ionic liquids. It is an energy-saving routes in industrial production without the need for heating equipment. Different catalysts were screened, and it was found that [Ru(p-cymene)Cl(2)](2) generated mono-olefinated products predominantly while [Cp*RhCl(2)](2) selectively gave di-olefinated products. These catalysts ([BMIM]NTf(2) and [BMIM]PF(6)) as green and recyclable reaction media are highly efficient under mild conditions. This reaction process can avoid any volatile and environmentally toxic organic solvents, and is much safer without the need for pressure-tight equipment. A wide substrate scope with good yields and satisfactory selectivity was achieved. The reactions can be scaled up to gram-scale. Furthermore, an expensive rhodium/ruthenium catalytic system was recycled for at least 6 times with consistently high catalytic activity, which was economical and environmental friendly from an industrial point of view. According to the mechanistic study, the C-H bond cleavage was probably achieved via the concerted metalation-deprotonation. This technique can be applied in the synthesis of various valuable unsaturated aromatic compounds and shows a great potential for industrial production" |
Notes: | "PubMed-not-MEDLINEDu, Kaifeng Yao, Tian eng England 2020/01/20 RSC Adv. 2020 Jan 20; 10(6):3203-3211. doi: 10.1039/c9ra09736h. eCollection 2020 Jan 16" |