X-Ray-induced retro [2 + 2] cycloaddition of a syn-tricyclo[4.2.0.02,5]octane derivative to a cis,cis-cycloocta-1,5-diene derivative within a single crystal lattice

Abstract

A syn-tricyclo[4.2.0.0^2,5]octane derivative 1, obtained from the high-pressure cycloaddition reaction of dimethyl 1,4-dimethyl-7-oxabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate 3 with cyclootatetraene 4, isomerizes on exposure to X-ray radiation to a cis,cis-cycloocta-1,5-diene derivative 2 without disrupting the crystal structure.