Catalytic Enantioselective Dehydrogenative Si-O Coupling to Access Chiroptical Silicon-Stereogenic Siloxanes and Alkoxysilanes
Jiefeng Zhu, Shuyou Chen and Chuan He*
*Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China, Email: hecsustech.edu.cn
J. Zhu, S. Chen, C. He, J. Am. Chem. Soc., 2021, 143, 5301-5307.
DOI: 10.1021/jacs.1c01106 (free Supporting Information)
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A rhodium-catalyzed intermolecular dehydrogenative Si-O coupling between dihydrosilanes and silanols or alcohols provides various highly functionalized chiral siloxanes and alkoxysilanes in decent yields with excellent stereocontrol.
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Synthesis of alkoxysilanes
To a 10 mL vial were in order added [Rh(cod)Cl]2 (1.0 mg, 1 mol%), ligand (2.4 mg, 2.2 mol%), toluene (2 mL), dihydrosilane substrate (0.24 mmol. 1.2 equiv), alcohol substrate (0.2 mmol, 1.0 equiv) in a glovebox under argon. The tube was capped, then removed from the glovebox and stirred at room temperature overnight. After the reaction completed, the reaction mixture was filtered through a short silica gel pad and evaporated under reduced pressure, then purified by preparative TLC to afford target product. The enantiomeric excess was determined by chiral HPLC analysis. Corresponding racemic samples were obtained as references by carrying out the reactions at the identical conditions with (±)-BINAP or (±)-Josiphos.