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Synthesis of 1,1-silylboranes and silylboronates

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Enantioenriched 1,1-silylboryl alkanes are highly valued building blocks in asymmetric synthesis as well as medicinal chemistry. An enantioselective cobalt-catalyzed hydrosilylation/hydroboration cascade of terminal alkynes offers chemo-, regio-, and stereoselectivity exquisitely controlled by a single set of metal catalyst and ligand.
S. Jin, K. Liu, S. Wang, Q. Song, J. Am. Chem. Soc., 2021, 143, 13124-13134.

A convenient method for the synthesis of 1,1-diboronates from the corresponding N-tosylhydrazones is also applicable to 1-silyl-1-boron compounds. Derivatization and consecutive Pd-catalyzed cross-coupling reactions with 1,1-boronates were also explored, demonstrating the synthetic potential of 1,1-diboronates.
H. Li, X. Shangguan, Z. Zhang, S. Huang, Y. Zhang, J. Wang, Org. Lett., 2014, 16, 448-451.

A base-mediated borylsilylation of benzylic ammonium salts provides geminal silylboronates bearing benzylic proton under mild reaction conditions. Deaminative silylation of aryl ammonium salts was also achieved in the presence of LiOtBu. Both methods offer high efficiency, mild reaction conditions, and good functional group tolerance for late-stage functionalization of amines.
W.-Y. Qi, J.-S. Zhen, X.-h. Xu, X. Du, Y.-h. Li, H. Yuan, Y.-S. Guan, X. Wei, Z.-Y. Wang, G. Liang, Y. Luo, Org. Lett., 2021, 23, 5988-5992.

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A (diiodo(trimethylsilyl)methyl)boronic ester was synthesized in a 4-step sequence using inexpensive and commercially available starting materials. The use of this carbene precursor in an organocatalyzed and visible light mediated borosilylcyclopropanation of styrene provides 1,1,2-tri- and 1,1,2,2-tetrasubstituted borosilylcyclopropanes in excellent yields and diastereoselectivity.
L. Thai-Savard, M. Sayes, J. Perreault-Dufour, G. Hong, L. A. Wells, M. C. Kozlowski, A. B. Charette, J. Org. Chem., 2023, 88, 1515-1521.