Astaxanthin intermediate, method for producing the same, and method for producing astaxanthin

摘要

Compounds of the general formula I IMAGE in which R1 is H or C1-C4-alkyl, R2 is C1-C4-alkyl and R3 is an ether, silyl ether or acetal protective group which can be converted into a hydroxyl group by hydrolysis, in particular one of the radicals IMAGE and a process for the production of these compounds by reacting an alkenyne of the general formula II IMAGE in an inert solvent with additional use of lithium amide with a cyclohexenone of the general formula III IMAGE and the use of the compounds of the formula I for the production of astaxanthin.