Photolysis (> 350 nm) of (2-phenoxyphenyl) phenyldiazomethane (1) in cyclohexane at 10° C gave the title compound (4), while similar irradiation with a shorter wavelength light (> 300 nm) afforded a mixture of the isomers (5–7), which were shown to be formed by photoisomerization of the initially formed 4.
[Calestani, Gianluca; Leardini, Rino; McNab, Hamish; Nanni, Daniele; Zanardi, Giuseppe Journal of the Chemical Society - Perkin Transactions 1, 1998 , # 11 p. 1813 - 1824]