Stereocontrolled First Total Syntheses of Amarouciaxanthin A and B

The first total syntheses of amarouciaxanthin A and B (C₄₀) via the stereoselective Wittig reaction of C₁₅-allenic and C₁₅-acetylenic tri-<i>n</i>-butylphosphonium salts with the unprecedented C₂₅-3,8-dihydroxy-5,6-epoxyapocarotenal have been completed. Oxidation of the two hydroxyl groups in the left part of the resulting condensation products followed by regioselective oxirane ring opening gave the target carotenoids