Gyroxanthin—the First Allenic Acetylenic Carotenoid

Selected recent studies on marine allenic and acetylenic carotenoids are focused on. The structure elucidation of gyroxanthin, (3S,5R,6S,3′S,5′R,6′R)-5,6-epoxy-6,7,7′,8′-tetradehydro-5,6,5′,6′-tetrahydro-β,β-carotene-3,19,3′,5′-tetrol, is reported in detail and in historical perspective. Gyroxanthin occurs as a diester (19-dodecanoate 3′-acetate) in the dinoflagellate Gymnodinium galatheanum.