Cyclohexenone derivatives and process for making same

摘要

A silyl-enol ether of the formula <IMAGE> I wherein n stands for the number and X stands for a group <IMAGE> or n stands for the number 1 and X stands for the 6,11-dimethylhexadeca-2,4,6,8,10,12,14-heptaene-2,15-diyl group, the symbols R1 have the same or different significances and denote alkyl groups, and the symbol R2 represents a trialkylsiloxy group -OSi(R1)3 or an ether group, is oxidized with percarboxylic acid and, if desired, the resulting alpha -siloxy ketone is hydrolyzed to an alpha -hydroxy ketone. This process is especially suitable for the manufacture of astaxanthin.