| abstract |
A process for preparing polyenecarbonyl compounds having a high all-E content and their acetals or ketals by aldol condensation or Horner-Emmons reaction comprises carrying out the reaction, for the purposes of the preferred formation of a double bond of E configuration and in order to obtain the E configuration of the double bonds in the starting compounds as completely as possible, in the presence of oxygen or an oxygen-inert gas mixture or nit-ric oxide or a nitric oxide-inert gas mixture and/or in the pre-sence of specific stable radicals and/or in the presence of quin-ones or quinone derivatives. |