Photoinduced Rearrangements of Diarylethenes

The photocyclization of stilbenes and their heterocyclic analogs has gained major importance in the synthesis of poly(hetero)aromatic compounds. This reaction generally leads to the formation of phenanthrene derivatives or their isosteric heterocyclic analogs. Over the last 15 years, examples of a new type of diarylethene reactions have been published, leading to bicyclic, instead of tricyclic aromatic products. These reactions are based on a sigmatropic hydrogen shift followed by the opening of one aromatic ring, and these transformations are applicable to the preparation of various aromatic compounds. Similar reactions are also highly relevant to the photostability of photochromic diarylethenes and terarylenes, thus the study of these compounds is important for the development of photo-controlled advanced materials and devices. In this review we provide the first analysis of scientific literature on this new type of diarylethene photoreactions.