Oxidative C-H bond functionalization and ring expansion with TMSCHN2 : a copper(I)-catalyzed approach to dibenzoxepines and dibenzoazepines.

Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for the pharmaceutical industry and academic research. However, their syntheses are generally rather tedious, requiring several steps that involve a Wagner-Meerwein-type rearrangement under harsh conditions. Herein, we present the first copper(I)-catalyzed oxidative CH bond functionalization and ring expansion with TMSCHN2 to yield these important derivatives in a facile and straightforward way.