A simple and mild photoredox catalytic approach to access difluoroalkylated dioxodibenzothiazepines in high regioselectivity via radical cascadecyclization has been described herein. In contrast to previous methods, this strategy does not involve the use of transition-metal catalysts and avoids the potential disadvantages of inevitable toxicity and the tedious removal process of metal catalysts. The
Abstract The cyclization reaction of 2-ethynyl- N -sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K 2 CO 3 under transition metal-free condition to give indoles in high yields. The recovery and reusability of the present catalytic system were investigated.
摘要在无过渡金属条件下,在催化量的K 2 CO 3存在下,2-乙炔基-N-磺酰腈在水中的环化反应有效地进行,从而获得了高产率的吲哚。研究了本催化体系的回收率和可重复使用性。
Harnessing sunlight without a photosensitizer for highly efficient consecutive [3+2]/[4+2] annulation to synthesize fused benzobicyclic skeletons
A photosensitizer-free, highly efficient sunlight-promoted tandem [3+2]/[4+2] annulation of unsaturated α-bromocarbonyls with o-alkynylanilines was developed, and allowed for convenient synthesis of fused benzobicyclic skeletons. The reaction was clean and practical in mild conditions and showed excellent functional group compatibility.
Two direct synthetic methods of 1,2,3,4-tetrahydro-β-carboline derivatives have been developed. After initial indole formation by copper-catalyzed domino three-component coupling−cyclization using an appropriate ethynylaniline, aldehyde, and a secondary amine, treatment with t-BuOK/hexane or MsOH afforded the desired tetrahydro-β-carboline derivatives in moderate to good yields.