CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China.
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520-8105, USA.
Angew Chem Int Ed Engl. 2021 Apr 19;60(17):9493-9499. doi: 10.1002/anie.202016081. Epub 2021 Mar 18.
Catalytic asymmetric remote conjugate borylation is challenging as the control of regioselectivity is not trivial, the electrophilicity of remote sites is extenuated, and the remote asymmetric induction away from the carbonyl group is difficult. Herein, catalytic asymmetric conjugate 1,6-, 1,8- and 1,10-borylation was developed with excellent regioselectivity, which delivered α-chiral boronates in moderate to high yields with high enantioselectivity. The produced chiral boronate smoothly underwent oxidation, cross-coupling, and one-carbon homologation to give synthetically versatile chiral compounds in moderate yields with excellent stereoretention. Furthermore, a stereomechanistic analysis was conducted using DFT calculations, which provides insights into the origins of the regioselectivity. Finally, the present 1,6-borylation was successfully applied in an efficient one-pot asymmetric synthesis of (-)-7,8-dihydrokavain.
催化不对称远程共轭硼化具有挑战性，因为区域选择性的控制并不简单，远程位点的亲电性减弱，并且远离羰基的远程不对称诱导很困难。在此，开发了具有优异区域选择性的催化不对称 1,6-、1,8-和 1,10-硼化反应，以中等至高产率和高对映选择性得到α-手性硼酸酯。生成的手性硼酸酯可顺利进行氧化、交叉偶联和一碳同系化反应，以中等收率和优异的立体选择性得到具有合成多功能性的手性化合物。此外，使用 DFT 计算进行了立体机理分析，为区域选择性的起源提供了深入的了解。最后，本 1,6-硼化成功应用于(-)-7,8-二氢卡瓦因的高效一锅不对称合成中。
