Liu Jiawang, Nie Ming, Zhou Qinghai, Gao Shen, Jiang Wenhao, Chung Lung Wa, Tang Wenjun, Ding Kuiling
State Key Laboratory of Organometallic Chemistry , State Key Laboratory of Bio-Organic and Natural Products Chemistry , Shanghai Institute of Organic Chemistry , Chinese Academy of Sciences , 345 Ling Ling Rd , Shanghai 200032 , China . Email:
Department of Chemistry , South University of Science and Technology of China , Shenzhen 518055 , China . Email:
Chem Sci. 2017 Jul 1;8(7):5161-5165. doi: 10.1039/c7sc01254c. Epub 2017 May 16.
A practical and enantioselective palladium-catalyzed diboration of 1,1-disubstituted allenes is developed by employing a P-chiral monophosphorus ligand, BI-DIME. A series of diboronic esters containing a chiral tertiary boronic ester moiety are formed in excellent yields and ee's with the palladium loading as low as 0.2 mol%. DFT calculations revealed a concerted mechanism of oxidative addition of bis(pinacolato)diboron and allene insertion, as well as a critical dispersion effect on the origins of the enantioselectivity. The method is successfully applied to the concise and enantioselective synthesis of brassinazole.
通过使用P-手性单磷配体BI-DIME，开发了一种实用且对映选择性的钯催化1,1-二取代丙二烯双硼化反应。一系列含有手性叔硼酸酯部分的双硼酸酯以优异的产率和对映体过量值形成，钯负载量低至0.2 mol%。密度泛函理论计算揭示了双(频哪醇合)二硼的氧化加成和丙二烯插入的协同机理，以及对映选择性起源的关键色散效应。该方法成功应用于油菜素唑的简洁且对映选择性合成。
