Generation by retro-ene reaction of cyclohex-2-enethione and cyclopent-2-enethione

Article abstract of DOI:10.1016/S0040-4039(97)10340-9

The reactive unsubstituted cyclohex-2-enethione (1) and cyclopent-2-enethione (2) have been synthesized in two steps (yields ca 70%) from the corresponding cycloalkenyl bromides. The key step is a retro-ene reaction under FVT conditions. The purple-blue thioketones 1 and 2, polymerizing rapidly above -80°C in the condensed phase, have been characterized by UV-visible and IR spectroscopy at -196°C, as well as, in the gas phase, by direct FVT/HRMS coupling. The reaction of 2 with diazomethane in THF led to 1,3-dithiolane 9.