Regioselective Late-stage Functionalization of Tetraphenylenes: Rapid Construction of Double Helical Architectures and Potential Hole Transport Materials

Abstract

Herein we report a novel approach for diversification of tetraphenylene via regioselective late-stage iodination follow by atom(s) insertion to the resulted cyclic iodonium salts. Thus, steric hindrance effect of tert-butyl facilitates the regioselective synthesis of two cyclic iodonium salts of 2,7,10,15-tetra-tert-butyltetraphenylene. In addition, two more cyclic iodonium salts of 2,7,10,15-tetranitrotetraphenylene were also readily synthesized due to the meta–position induced effect of the electron–withdrawing NO2 group. Subsequent functionalization of these tetraphenylene-based cyclic iodonium salts via diverse atom(s) insertion processes led to several tetraphenylene-based [8+n] and [n+8+n] fused rings including the fascinating double helical architectures. This newly developed late-stage functionalization methodology was also successfully applied to rapid synthesis of potential hole transport materials, thereby demonstrating its robust synthetic value in both tetraphenylene chemistry and materials science.