Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. IX. Synthese von (3R)‐Hydroxyechinenon, (3R, 3′R)‐ und (3R, 3′S)‐Adonixanthin, (3R)‐Adonirubin, deren optischen Antipoden und verwandten Verbindungen

Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. IX. Synthesis of (3R)‐Hydroxyechinenone, (3R, 3′R)‐ and (3R, 3′S)‐Adonixanthin, (3R)‐Adonirubin, Their Optical Antipodes and Related Compounds The synthesis of racemic and optically active hydroxyechinenone (12–14), adonixanthin (16–19), adonirubin (22–24), meso‐astaxanthin (26) and their corresponding diosphenols 15, 20, 21, 25, 27, 28, and 29) by Wittig reaction is reported, starting from suitable C15‐phosphonium salts and C10‐aldehydes.