General Synthesis of Trialkyl- and Dialkylarylsilylboranes: Versatile Silicon Nucleophiles in Organic Synthesis
Ryosuke Shishido, Minami Uesugi, Rikuro Takahashi, Tsuyoshi Mita, Tatsuo Ishiyama, Koji Kubota* and Hajime Ito*
*Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan,
Email: kbt
eng.hokudai.ac.jp, hajitoeng.hokudai.ac.jp
R. Shishido, M. Uesugi, R. Takahashi, T. Mita, T. Ishiyama, K. Kubota, H. Ito, J. Am. Chem. Soc., 2020, 142, 14125-14133.
DOI: 10.1021/jacs.0c03011
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Abstract
Silylboranes are nucleophilic silylation reagents that can be activated by transition-metal catalysts or bases. Rh- and Pt-catalyzed direct borylations of hydrosilanes with bis(pinacolato)diboron enable the synthesis of trialkylsilylboranes that bear bulky alkyl groups as well as functionalized dialkylarylsilylboranes that are difficult to synthesize via conventional methods using alkali metals.
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proposed mechanism
Details
The article discusses the development of new methods for synthesizing trialkyl- and dialkylarylsilylboranes, which are versatile silicon nucleophiles in organic synthesis. The authors, led by Koji Kubota and Hajime Ito, utilized rhodium and platinum catalysts for the direct borylation of hydrosilanes with bis(pinacolato)diboron. This approach allows the creation of new silylboranes with bulky alkyl and functional groups, which were previously difficult to synthesize. The study demonstrates that these new silylboranes can be used as silicon nucleophiles in various organic transformations, significantly expanding the range of accessible organosilicon compounds. The Rh-based catalytic system is particularly effective for sterically hindered trialkylsilanes, while the Pt-based catalyst shows high chemoselectivity for functionalized silylboranes. The research also provides the first NMR spectroscopic evidence for the formation of i-Pr3SiLi. These findings are expected to inspire the development of new silicon-containing bioactive molecules and organic materials with desirable properties. The study was supported by several Japanese research grants and institutions, and the authors declare no competing financial interests.
Key Words
ID: J48-Y2020
