Morris Scott A, Nguyen Theresa H, Zheng Nan
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States.
Adv Synth Catal. 2015 Jul 6;357(10):2311-2316. doi: 10.1002/adsc.201500317. Epub 2015 Jul 14.
The synthesis of fused -arylindolines using visible light photoredox catalysis has been developed. We previously described that photogenerated amine radical cations generate substituted indoles through an intermediate benzylic carbocation. Herein, we expand the application of this chemistry by trapping the benzylic carbocation with tethered heteronucleophiles. The reactivity of the photogenerated benzylic carbocation is explored and applied to a range of substrates with various electronic characters and ring constraints. The method described provides C2 and C3 fused indolines bearing a tetrasubstituted carbon stereocenter with greater than 99:1 diastereoselectivity in moderate to good yields.
利用可见光光氧化还原催化合成稠合芳基吲哚啉的方法已被开发出来。我们之前描述过，光生胺自由基阳离子通过中间体苄基碳正离子生成取代吲哚。在此，我们通过用连接的异亲核试剂捕获苄基碳正离子来扩展这种化学方法的应用。研究了光生苄基碳正离子的反应活性，并将其应用于一系列具有不同电子特性和环限制的底物。所描述的方法以中等至良好的产率提供了带有四取代碳立体中心的C2和C3稠合吲哚啉，非对映选择性大于99:1。
