Intramolecular cycloaddition of fluorinated 1,3,4-oxadiazoles to dienes

Cycloaddition reactions of fluorinated 1,3,4-oxadiazoles with conjugated and unconjugated dienes was studied. The reactions resulted in the formation of products of double cycloaddition (7-oxabicycloheptane type compounds), along with products of intramolecular cycloaddition (oxatricyclic and oxatetracyclic compounds). The structure of 4-(trifluoromethyl)-2-ethoxycarbonyl-1,6-dimethyl-3-oxatricyclo[2.2.1.02,6]heptane was confirmed by single crystal X-ray diffraction analysis.