Angelw: Professor Hou Zhaomin's research group of Japan Institute of physics and chemistry realizes silicification of terminal alkyne hydrocarbon bond

The author of this paper: Ma Yuanhong's organosilicon compounds, such as aryl silicide and alkynyl silicide, are widely used in the structural units of drugs and materials They have attracted much attention in synthetic chemistry due to their advantages of stability, low toxicity and good functional group compatibility Therefore, how to synthesize organosilicon compounds efficiently has been a hot topic in the field of synthesis From the point of view of atomic economy, it is one of the most attractive methods for C − H bond and hydrosilane to produce silicide products by releasing a molecule of hydrogen So far, this kind of catalytic process is mainly realized by transition metal complexes, alkali metal salts and other catalysts In recent years, with the rapid development of hindered Lewis pairs (FLPs) chemistry, electron deficient boranes and their analogues such as B (C6F5) 3 have attracted the attention of synthetic chemists Among them, electron deficient borane can be used as excellent Si − H bond activation catalyst Based on this basic concept, the research group of Professor Hou Zhaomin of Japan Institute of science and chemistry has made a series of important achievements In 2016, the research group realized the coupling reaction of boron catalyzed dehydrogenation of electron rich aromatic compounds and hydrosilanes (j.am.chem.soc 2016, 138, 3663), representing the first case of metal free dehydrogenation and silicification In 2017, the research group reported the boron catalyzed C − Si / Si − H cross decomposition reaction, providing a new type of carbon silicon bond building reaction (j.am.chem.soc 2017, 139, 12434) Recently, Professor Hou Zhaomin's research group has made important progress in the field of boron catalyzed silanization By combining B (C6F5) 3 with organic bases such as triethylenediamine (DABCO), the group realized the dehydosilicization of terminal alkyne C − H bond and hydrosilane with high efficiency and selectivity On the other hand, there are only a few reports about the functionalization of C-H bond catalyzed by electron deficient borane The current catalytic reaction represents the first case of C (SP) - H bond conversion catalyzed by borane The catalytic system shows the advantages of wide range of substrate application, high chemical selectivity, no need of hydrogen acceptor and large-scale synthesis of gram (Fig 1) Figure 1 B (C6F5) 3 / alkali catalyzed C − H bond silicification reaction (source: angel Chem Int ed.) deputy researcher Logan of Dalian University of technology conducted an in-depth study on the mechanism of the current reaction system by using DFT calculation and experiments B (C6F5) 3 and DABCO react with alkyne in FLP activation mode to form intermediate I, which is reversible under experimental conditions On the other hand, B (C6F5) 3 can activate hydrosilane with the aid of DABCO, and generate ion pair intermediate III via transition state II; then it can react with alkyne and DABCO to generate target silicide product, DABCO and ion pair species V via transition state IV; finally, V Releases Renewable B (C6F5) 3 and DABCO along with hydrogen This mechanism suggests that DABCO plays a very important dual role: as a cationic silicon intermediate for Lewis base stable activation, and as a Br? Nsted base to promote C − H bond depolymerization of terminal alkynes (Fig 2) Figure 2 Schematic diagram of reaction mechanism (source: angelw Chem Int ed.) This achievement was published on angelw Chem Int ed (DOI: 10.1002 / anie 201809533) under the title of "B (C6F5) 3 / amine catalyzed C (SP) - H silationof terminal alkynes with hydrosilanes: experimental and theoretical studies" Professor Hou Zhaomin and associate researcher Luo Gen are the corresponding authors of the paper, and postdoctoral researcher Ma Yuanhong of Japan Institute of science and chemistry is the first author of the paper Professor Luo Yi of Dalian University of technology also gave a lot of suggestions and discussions for this topic.