Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore.
Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China.
Nat Chem. 2023 May;15(5):666-676. doi: 10.1038/s41557-023-01155-8. Epub 2023 Mar 9.
Organosilanes are of vital importance for modern human society, having found widespread applications in functional materials, organic synthesis, drug discovery and life sciences. However, their preparation remains far from trivial, and on-demand synthesis of heteroleptic substituted silicon reagents is a formidable challenge. The generation of silyl radicals from hydrosilanes via direct hydrogen-atom-transfer (HAT) photocatalysis represents the most atom-, step-, redox- and catalyst-economic pathway for the activation of hydrosilanes. Here, in view of the green characteristics of neutral eosin Y (such as its abundance, low cost, metal-free nature, absorption of visible light and excellent selectivity), we show that using it as a direct HAT photocatalyst enables the stepwise custom functionalization of multihydrosilanes, giving access to fully substituted silicon compounds. By exploiting this strategy, we realize preferable hydrogen abstraction of Si-H bonds in the presence of active C-H bonds, diverse functionalization of hydrosilanes (for example, alkylation, vinylation, allylation, arylation, deuteration, oxidation and halogenation), and remarkably selective monofunctionalization of di- and trihydrosilanes.
有机硅烷对现代人类社会至关重要，在功能材料、有机合成、药物发现和生命科学领域有广泛应用。然而，其制备远非易事，而按需合成杂取代硅试剂则是一个巨大的挑战。通过直接氢原子转移（HAT）光催化从硅烷生成硅自由基，是硅烷活化最原子经济型、步骤经济性、氧化还原经济性和催化剂经济型的途径。鉴于中性曙红 Y 的绿色特性（如丰富、廉价、无金属、可见光吸收和出色的选择性），我们发现可以将其作为直接 HAT 光催化剂，分步实现多硅烷的定制功能化，得到完全取代的硅化合物。通过利用这一策略，我们可以在存在活泼 C-H 键的情况下优先进行 Si-H 键的氢提取，对硅烷进行多样化的功能化（例如烷基化、乙烯基化、烯丙基化、芳基化、氘代、氧化和卤化），并显著选择性地对二硅烷和三硅烷进行单官能化。
