Cui Chunming research group of Nankai: selective hydrosilylation of internal olefins catalyzed by rare earth metals

Catalytic hydrosilylation of olefins is one of the most effective methods to prepare organosilicon reagents, which is widely used in organic synthesis and industrial production However, the carbon carbon double bond of olefin substrate is generally in the end group, and there are many kinds of multi substituted olefins with wide distribution Due to the large steric resistance and the small difference between the two ends of the double bond, its catalytic efficiency is still very low There are many problems such as low yield, poor selectivity and limited application of substrate Therefore, it is urgent to develop new catalytic systems to achieve high efficiency hydrosilylation of multi substituted olefins Rare earth elements are rich in reserves and cheap in price They are widely used in daily life and industrial production, especially in new energy, new materials and other high-tech fields They are important national strategic elements in China Due to the unique electronic structure of rare earth metals, their organometallic catalysts mainly adopt the mechanism of σ - bond decomposition and coordination insertion in the catalytic cycle Therefore, in many catalytic transformations, rare earth metal catalysts show completely different substrate application scope and selectivity from transition metal catalysts, forming beneficial complementarities with them in homogeneous catalysis field In addition, the rare earth catalytic reaction has the characteristics of fast reaction, mild condition and single route Professor Cui Chunming's research group of Nankai University has been engaged in the synthesis and reactivity research of new rare earth organic compounds A new reaction model was developed based on the investigation of elementary reaction, structure-activity relationship and reaction mechanism Finally, the new chemical transformation with high efficiency is realized Recently, a highly efficient alkenyl diamine samarium alkyl catalyst has been prepared by our group through novel and simple oxidation-reduction and salt elimination reactions It is the first time to realize the high activity and high regioselectivity catalytic hydrosilylation of internal alkenes In order to study the catalytic mechanism, the group further investigated the σ - bond decomposition reaction of the rare earth alkyl compound and silane, and found that the reaction can generate rare earth hydrides quickly and equivalently, and carried out the structure characterization such as separation and X-ray single crystal diffraction It is also proved that the samarium hydride is the active center of hydrosilylation At the same time, the catalytic mechanism of complex decomposition insertion was put forward through the study of kinetics and the previous work of the research group Relevant achievements were published on ACS catalyst (ACS catalyst 2018, 8, 2230) The above research was supported by NSFC, State Key Laboratory of elemental organic chemistry, School of chemistry, Nankai University and Tianjin collaborative innovation center of chemical industry Paper information: Jinxi Liu, Wufeng Chen, Jianfeng Li *, Chung Cui *, rare earth catalyzed regioselective hydrolization of aryl substituted internal alkenes, ACS catalyst., 2018, 8, 2230 – 2235