A Versatile NHC-Parent Silyliumylidene Cation for Catalytic Chemo- and Regioselective Hydroboration
| Autor: | Jiawen Lee, Yan Li, Chi-Kit Siu, Ming-Der Su, Bi-Xiang Leong, Cheuk-Wai So, Ming-Chung Yang |
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| Přispěvatelé: | School of Physical and Mathematical Sciences |
| Rok vydání: | 2019 |
| Předmět: |
Silicon
Hydride Chemistry Regioselectivity chemistry.chemical_element General Chemistry N-heterocyclic Silylene 010402 general chemistry 01 natural sciences Biochemistry Medicinal chemistry Catalysis 0104 chemical sciences chemistry.chemical_compound Hydroboration Colloid and Surface Chemistry Chemistry [Science] Reactivity (chemistry) Organic synthesis Stable Silylene |
| Zdroj: | Journal of the American Chemical Society. 141(44) |
| ISSN: | 1520-5126 |
| Popis: | This study describes the first use of a silicon(II) complex, NHC-parent silyliumylidene cation complex [(IMe)2SiH]I (1, IMe = :C{N(Me)C(Me)}2) as a versatile catalyst in organic synthesis. Complex 1 (loading: 10 mol %) was shown to act as an efficient catalyst (reaction time: 0.08 h, yield: 94%, TOF = 113.2 h-1; reaction time: 0.17 h, yield: 98%, TOF = 58.7 h-1) for the selective reduction of CO2 with pinacolborane (HBpin) to form the primarily reduced formoxyborane [pinBOC(═O)H]. The activity is better than the currently available base-metal catalysts used for this reaction. It also catalyzed the chemo- and regioselective hydroboration of carbonyl compounds and pyridine derivatives to form borate esters and N-boryl-1,4-dihydropyridine derivatives with quantitative conversions, respectively. Mechanistic studies show that the silicon(II) center in complex 1 activated the substrates and then mediated the catalytic hydroboration. In addition, complex 1 was slightly converted into the NHC-borylsilyliumylidene complex [(IMe)2SiBpin]I (3) in the catalysis, which was also able to mediate the catalytic hydroboration. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) This work is supported by an ASTAR SERC PSF grant and AcRF Tier 1 grant (C.-W.S.). M.-C.Y. and M.-D.S. are grateful to the National Center for High-Performance Computing of Taiwan for generous amounts of computing time and the Ministry of Science and Technology of Taiwan for the financial support. |
| Databáze: | OpenAIRE |
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