Yamagishi Hiroki, Hitoshio Kenshiro, Shimokawa Jun, Yorimitsu Hideki
Department of Chemistry, Graduate School of Science, Kyoto University Sakyo-ku Kyoto 606-8502 Japan
Chem Sci. 2022 Mar 21;13(15):4334-4340. doi: 10.1039/d2sc00227b. eCollection 2022 Apr 13.
Silylcoppers function as convenient and effective sources of silicon functional groups. Commonly used precursors for those species have been limited to certain symmetric disilanes and silylboranes. This fact renders the development of silylcopper precursors desirable so that more diverse silyl groups could be efficiently delivered. Here we extend the utility of sodium silylsilanolates as competent precursors of silylcoppers. A silanolate unit operates as an auxiliary to transfer a variety of silyl groups to the copper centre, which was demonstrated in the copper-catalysed hydrosilylation of internal alkynes, α,β-unsaturated ketones, and allenes. Our mechanistic studies through DFT calculation suggested that a copper silylsilanolate undergoes intramolecular oxidative addition of the Si-Si bond to the copper centre to generate a silylcopper, in contrast to the typical formal σ-bond metathesis mechanism for conventional disilanes or silylboranes and copper alkoxides. Accordingly, sodium silylsilanolate has been established as an expeditious precursor of a variety of silylcopper species.
硅基铜可作为硅官能团便捷且有效的来源。常用于这些物种的前体仅限于某些对称二硅烷和硅硼烷。这一事实使得开发硅基铜前体变得很有必要，以便能更高效地提供更多样化的硅基。在此，我们拓展了硅硅醇钠作为硅基铜有效前体的用途。硅醇盐单元作为辅助基团，将各种硅基转移至铜中心，这在铜催化的内炔、α,β-不饱和酮和丙二烯的硅氢化反应中得到了证明。我们通过密度泛函理论计算进行的机理研究表明，与传统二硅烷、硅硼烷和铜醇盐典型的形式σ键复分解机理不同，硅硅醇钠铜会发生Si-Si键向铜中心的分子内氧化加成，从而生成硅基铜。因此，硅硅醇钠已被确立为多种硅基铜物种的快速前体。
