Highly Enantioselective [2+2+2] Cycloaddition of Enediynes Enabled by Cobalt/Organophotoredox Cooperative Catalysis
作者:Takeshi Yasui、Rine Tatsumi、Yoshihiko Yamamoto
DOI:10.1021/acscatal.1c02410
日期:2021.8.6
Herein, we report dual cobalt and photoredox catalysis enabled [2+2+2] cycloaddition of enediynes to produce tricyclic cyclohexadienes bearing a quaternary bridgehead carbon. A variety of enediynes were used, and the corresponding cyclohexadienes were obtained in good to high yields. The use of a chiral ligand, (S)-Segphos, enabled a highly enantioselective reaction allowing access to highly enantio-enriched
在此,我们报告了双钴和光氧化还原催化使烯二炔的 [2+2+2] 环加成产生带有四元桥头碳的三环环己二烯。使用了多种烯二炔,并以良好到高产率获得了相应的环己二烯。手性配体 ( S )-Segphos 的使用可实现高度对映选择性反应,从而获得高度对映体富集的环己二烯。
A Straightforward Procedure for the [2+2+2] Cycloaddition of Enediynes
Enediynes undergo intramolecular [2+2+2] cycloaddition in the presence of cobalt(II) iodide (CoI2), manganese and an N-heterocyclic carbene (IPr) generated in situ from the corresponding imidazolium salt and butyllithium (BuLi). Polycyclic cyclohexadienes are obtained selectively. This new method represents an interesting alternative to those employing air-sensitive cyclopentadienylcobalt [CpCoL2 (L=CO