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

Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. IX. Synthesis of (3 R )‐Hydroxyechinenone, (3 R , 3′ R )‐ and (3 R , 3′ S )‐Adonixanthin, (3 R )‐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 C 15 ‐phosphonium salts and C 10 ‐aldehydes.