Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore.
Angew Chem Int Ed Engl. 2019 Feb 18;58(8):2382-2386. doi: 10.1002/anie.201813490. Epub 2019 Jan 24.
An enantioconvergent synthesis of chiral cyclic allylboronates from racemic allylic bromides was achieved by using a guanidine-copper catalyst. The allylboronates were obtained with high γ/α regioselectivities (up to 99:1) and enantioselectivities (up to 99 % ee), and could be further transformed into diverse functionalized allylic compounds without erosion of optical purity. Experimental and DFT mechanistic studies support an S 2' borylation process catalyzed by a monodentate guanidine-copper(I) complex that proceeds through a special direct enantioconvergent transformation mechanism.
通过使用胍-铜催化剂，实现了从外消旋烯丙基溴化物到手性环状烯丙基硼酸酯的对映选择性转化的对映汇聚合成。手性烯丙基硼酸酯以高γ/α区域选择性（高达 99:1）和对映选择性（高达 99%ee）获得，并且可以在不破坏光学纯度的情况下进一步转化为各种功能化的烯丙基化合物。实验和 DFT 机理研究支持单齿胍-铜（I）配合物催化的 S 2'硼化过程，该过程通过特殊的直接对映选择性转化机制进行。
