Convenient construction of tetraphenylethene (TPE) derivatives through Cu(ii) mediated cascade dehydrogenation of EWG-activated diphenylmethane

Tetraphenylethene (TPE) is a prototypical structural motif frequently found to be incorporated into materials related to aggregation-induced emission (AIE), covalent-organic frameworks (COF), molecular cages etc., and is often synthesized by conventional McMurry coupling and Rathore's procedure. However, those traditional approaches generally show limited functional-group compatibility to strong electron-withdrawing groups such as nitro, cyano, carbonyl, etc. Here, we report a C-H tandem oxidative homocoupling strategy for constructing electron-deficient TPEs using easily accessible activated diphenylmethane. This process is scalable and easily handled. In particular, the TPE derivatives with nitro attachments were unexpectedly found to react with a series of nucleophiles directly, a merit that would contribute to the diversity of the TPEs.