Synthesen in der Carotinoid‐Reihe Mitteilung. Totalsynthese von Zeaxanthin und Physalien

Zeaxanthin and physalien have been synthesized from acetoxyiso‐C19‐aldehyde and acetylene following the scheme C19+ C2+ C19 = C40. The acetoxy‐iso‐C19‐aldehyde was obtained from isophorone via keto‐iso‐C19‐aldehyde to which the chain lengthening procedure of our β‐carotene synthesis was applied, using vinyl ether and propenyl ether. The optically inactive synthetic compounds have the same melting points as the natural products, the absorption spectra of the solutions are identical, and the mixed melting points show no depression.