An effective and versatile strategy for the synthesis of structurally diverse heteroarylsilanes via Ir(iii )-catalyzed C–H silylation
| Autor: | Fu-Min Zhang, Ka Lu, Zhi-Bo Yan, Yong-Qiang Tu, Xiao-Ming Zhang, Qi-Long Chen, Meng Peng, Kun-Long Dai |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Chemical Science. 12:9748-9753 |
| ISSN: | 2041-6539 2041-6520 |
| Popis: | A versatile silylation of heteroaryl C–H bonds is accomplished under the catalysis of a well-defined spirocyclic NHC Ir(III) complex (SNIr), generating a variety of heteroarylsilanes. A significant advantage of this catalytic system is that multiple types of intermolecular C–H silylation can be achieved using one catalytic system at α, β, γ, or δ positions of heteroatoms with excellent regioselectivities. Mechanistic experiments and DFT calculations indicate that the polycyclic ligand of SNIr can form an isolable cyclometalated intermediate, which leaves a phenyl dentate free and provides a hemi-open space for activating substrates. In general, favorable silylations occur at γ or δ positions of chelating heteroatoms, forming 5- or 6-membered C–Ir–N cyclic intermediates. If such an activation mode is prohibited sterically, silylations would take place at the α or β positions. The mechanistic studies would be helpful for further explaining the reactivity of the SNIr system. |
| Databáze: | OpenAIRE |
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