Metallocene pentaselenides and elemental selenium were employed in an effort to generate diatomic selenium (Se2) under thermal conditions. Trapping experiments were carried out with six dienes. A successful formation of a diselenium adduct was observed in the case of 5,6-dimethylene-cyclohexa-1,3-diene (1a). The other dienes produced the corresponding dihydroselenophenes. The in-depth study of the limitations of our method to generate Se2 is described; a plausible mechanism rationalizing the observed results is proposed.
Metallocene pentaselenides and elemental selenium were employed in an effort to generate diatomic selenium (Se2) under thermal conditions. Trapping experiments were carried out with six dienes. A successful formation of a diselenium adduct was observed in the case of 5,6-dimethylene-cyclohexa-1,3-diene (1a). The other dienes produced the corresponding dihydroselenophenes. The in-depth study of the limitations of our method to generate Se2 is described; a plausible mechanism rationalizing the observed results is proposed.