Formation of a Sterically Crowded 1,6,6αλ4-Triselenapentalene and 4H-Selenopyran-4-selones Fused with Two Bornane Skeletons Through the Reaction of d-Camphor p-Toluenesulfonylhydrazone With a Base and Elemental Selenium

Reaction of d-camphor p-toluenesulfonylhydrazone with t-butoxide and elemental selenium in dimethylformamide at an elevated temperature afforded a stable compound having a unique 1,6,6αλ4-triselenapentalene ring and 4 H-selenopyran-4-selones along with dialkenyl diselenide, dibornylenes, and 1,2,5-triselenepin, and the structural confirmation of these products were carried out by X-ray crystallographic analysis. The sterically crowded 1,6,6aλ4-triselenapentalene ring fused with two bornane sleketons was stable enough under aerobic exposure and was inactive toward sodium borohydride reduction but was converted into 1,2-diselenole derivative through m-chloroperbenzoic acid oxidation.