Generation and Rearrangement of Some Spirocycloaliphatic Thiosulfines and Dithiiranes

The flash‐vacuum pyrolysis of selected dispirodicycloaliphatic 1,2,4‐trithiolanes was studied by using matrix isolation techniques. The formation of thiosulfines and dithiiranes along with the corresponding thioketones was detected spectroscopically and confirmed by comparison with computed spectra. In the case of tetramethylcyclobutanone 1,2,4‐trithiolane, the thermal formation of the dithiolactone was observed. Pyrolysis of the (dichloro)tetramethylcyclobutane derivative resulted only in the formation of a mixture of the thiosulfine and dithiirane. In this case, conversion into the corresponding dithiolactone could be achieved photochemically. The dispirodiadamantane derivative gave a mixture of the respective thiosulfine and dithiirane but no dithiolactone could be detected in the mixture. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)