Modellreaktionen zur Biosynthese von Verbindungen der Damascon‐Reihe und ihre präparative Anwendung

We report a new general synthesis of damascones. In the presence of acids, 7, 8‐dehydro‐β‐ionole ( 10 ) or the related diols 11 are converted into a mixture of β‐damascone ( 2 ) and the 7, 8‐dehydrotheaspiranes ( 19 ). In the same way the 6‐hydroxy‐7, 8‐dehydro‐α‐ionoles 12 are transformed into a mixture of β‐damascenone ( 3 ) and the 8‐oxatheaspiranes ( 20 ). The reaction Provides access to damascone derivatives 4 – 7 which have been found in nature. These synthetic experiments lend support to our hypotheses concerning the biogenesis of damascones from suitable carotenoids or their metabolites.