Aerobic Dimerization of Ethyl 4‑Thienyl-3-ketobutanoate toward a Modifiable Photochromic Diarylethene Precursor

A unique chemical
transformation, the base-induced aerobic dimerization
of ethyl 4-(2,5-dimethylthiophen-3-yl)-3-ketobutanoate leading to
photochromic diarylethene with a 4-hydroxy-4-methylcyclopent-2-ene-1-one
as an ethene bridge, is described. This compound is easily subjected
to various chemical modifications and can be used as a new diarylethene
precursor to produce photoactive compounds with desired properties
and functions.