Synthesis and photorearrangement of furanone diarylethenes with an additional π-system

Abstract

In recent years, the synthetic potential of the photorearrangement of diarylethenes leading to naphthalene and phenanthrene derivatives via a cascade process of photocyclization/[1,9]-H shift has been demonstrated. In this work, the influence of various substituents on the efficiency of the photorearrangement of diarylethenes (DAEs) of the furanone series containing an additional π-system has been explored. It was found that electron-withdrawing substituents contribute only to the photocyclization process, while electron-donating groups (methoxy or dialkylamino groups) lead to E/Z-isomerization. However, in the case of dialkylamino substituted diarylethenes, the addition of a strong Brønsted acid promotes the photorearrangement, but prevents E/Z isomerization.