The highly strained cyclic allene 2,3-dihydro-2
H-thiopyran
2 was generated by irradiation of matrix-isolated 2-benzothienyltrifluorocarbene
1, and characterized by IR, UV/Vis spectroscopy and DFT modeling. At different wavelengths, the carbene rearranges to a quinone methide
3. The carbene
1, allene
2 and quinone methide
3 could be photochemically interconverted.
