Patent ID: 6610892
Filing Date: 2003-08-26
Classification: C07C,C07D

Abstract:
A process for preparing 2,7-dimethyl-2,4,6-octatrienal monoacetals of the general formula I, in which the substituents R1 and R2 may, independently of one another, be C1-C8-alkyl or, together with the oxygen atoms and the carbon atoms to which they are bonded, form a 1,3-dioxolane or 1,3-dioxane ring of the following structures in which R3 and R4, and R5 may each, independently of one another, be hydrogen or C1-C4-alkyl,which comprisesa) condensing an ester phosphonium salt of the general formula II or an ester phosphonate of the general formula III, in which the substituents have, independently of one another, the following meaning:R6 C1-C8-alkyl; R7 aryl; Xâˆ’ an anion equivalent of an inorganic or organic acid; R8 and R9 C1-C8-alkyl;with an aldehyde of the formula IV in a Wittig or Wittig-Horner reaction to give an acetal ester of the general formula V, in which the substituents R1, R2 and R6 in the compounds IV and V have the abovementioned meaning,b) reducing the ester of the formula V to an acetal alcohol of the general formula VI, andc) oxidizing the alcohol to 2,7-dimethyl-2,4,6-octatrienal monoacetals of the general formula I.