Synthese von Astaxanthin aus β-Jonon. I. Erschliessung der enantiomeren C15-Wittigsalze durch chemische und mikrobiologische Racematspaltung von (+/-)-3-Acetoxy-4-oxo-β-jonon

Article abstract of DOI:10.1002/hlca.19810640750

Racemic 3-acetoxy-4-oxo-β-ionone (10) was synthesized from the industrially accessible intermediate β-ionone (5).Resolution of 10 into its enantiomers was achieved via the corresponding diastereometric camphanates and by microbial resolution.Site-selective alkylation of racemic and of optically pure 3-acyloxy-4-oxo-β-ionones with vinyl magnesium chloride at -70 deg furnished the corresponding 3-acyloxy-4-oxo-9-vinyl-β-ionols which could be transformed to the Wittig salts 1, 3 and 4, respectively, following known procedures <1>.