Total Synthesis of Kealiiquinone, an Imidazole Marine Alkaloid

Abstract

The total synthesis of kealiiquinone (1), a highly substituted imidazole marine alkaloid isolated from sponge, was achieved via nine reaction steps starting from 1-methyl-1H-imidazole (5). The synthesis is based on the selective introduction of appropriate carbogenic substituents and protecting groups into the imidazole ring followed by an intramolecular cyclization of the substituents on the C4- and the C5-positions. The structure of the synthesized kealiiquinone was confirmed by X-ray crystallographic analysis.