Synthesis and Thiophene Ring Opening Reaction of [2]Paracyclo[2](2,5)-and -(2,4)thiophenophanes

Dithia[3]paracyclo[3](2,4)- and -(2,5)thiophenophanes 〈dithia-[3.3](2,4)- and -(2.5)PTP〉 (3, 7, 9) are obtained by the coupling reaction of the corresponding bis(chloromethyl)- and bis(mercaptomethyl)arenes. Desulfurization of the dithia[3.3]PTPs 3, 7, 9 by photolysis affords the thia[2.3]PTPs 15, 16, 17 and [2.2]PTPs 14, 18, 19, 20 The pyrolysis of the disulfone 12 gives the symmetrical thiophenophane 13. The dynamics of the ring inversion, the UV spectra, and the reductive ring opening with Raney-Ni (W-7) of the obtained PTPs are discussed.