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
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.