Photochromic C2-symmetric chiral diarylethene: from the initial state to the final state.

The behavior of 1,2-bis[(R)-2-(1-methoxymethoxyethyl)-3-benzo[b]thienyl] hexafluorocyclopentene before and upon UV irradiation and during thermal evolution of the photoirradiated solution has been thoroughly investigated by multinuclear NMR spectroscopy. A dynamic NMR study of the initial state was performed, providing a detailed description of the perceived conformational processes in the system. Before irradiation, three open conformations are in equilibrium, whereas UV irradiation generated the two expected cyclized diastereomers.

Ultimate diastereoselectivity in the ring closure of photochromic diarylethene possessing facial chirality.

A bisthienylethene with hitherto unprecedented facial chirality imposed by a triethyleneglycol bridge on a thiophene ring was synthesized and its photochromic ring closure was shown to occur with 100% diastereoselectivity upon UV-light irradiation.

A unified strategy for exceptionally high diastereoselectivity in the photochemical ring closure of chiral diarylethenes.

Into my arms: Photochemical cyclization of diarylethenes that have two chiral side arms showed up to 100% de (see scheme). Introduction of these chiral side arms onto the carbon atoms where ring closure occurs is a general strategy for the highly diastereoselective cyclization of diarylethenes.