A short access to highly strained spiranic compounds from ethyl 3-cyclobutylprop-2-enoate

UV irradiation of ethyl 3-cyclobutylpropen-2-oate delivered the β,γ-unsaturated isomer in high yield. Its CC double bond was submitted to epoxidation and cyclopropanation to deliver the corresponding spiro[3.2]hexane derivatives. Alternatively, the same substrate treated by TMS–I or by OsO4 allowed an easy access to two spiranic butyrolactones.