Electrochemically time-dependent oxidative coupling/coupling-cyclization reaction between heterocycles: tunable synthesis of polycyclic indole derivatives with fluorescence properties.

A mild and practical protocol for selectively time-dependent dehydrogenative C-C coupling, as well as tandem coupling-cyclization reaction between indoles or/and other heteroaromatics via electrochemically oxidative process has been demonstrated. The reaction runs under noble catalyst, external oxidant and inert gas free condition, allowing tunable access to a wide variety of synthetically useful symmetrical or nonsymmetrical heteroarene with aggregation-induced emission (AIE), and polycyclic 3-D indole derivatives with aggregation-caused quenching (ACQ) fluorescence properties. Finally, preliminary mechanistic study indicated that tunable generation of indole cation under various electrolysis potential via regulating N-protecting group was the key to achieve cross-coupling between indoles and other heteroaromatics. [ABSTRACT FROM AUTHOR]