3aH-indenes. Part 4. Formation and reactions of some dienone intermediates

Abstract

Methylation of the enolate anion of the cyclohexadienone (1) with methyl fluorosulphonate gave the unstable trienol ether (4) which was converted into the 4-phenyl-1,2,4-triazole-3,5-dione adduct (5) and the tricarbonyliron complex (6). The phenylseleno group of the triene (4) could not be oxidatively eliminated, under various conditions, to give the tetraene (3), but it was eliminated from the adduct (5) to give the rearranged adduct (9). The best reagent for selenide oxidation and elimination was chloramine-T under phase-transfer conditions. This was very effective in the conversion of the selenide (12) into the dienone (13). The dienone (15) was also prepared from the selenide (14).