Process for preparing (2E,6Z)-2,6-nonadienal and a process for preparing (2E)-cis 6,7-epoxy-2-nonenal

A process for preparing (2E,6Z)-2,6-nonadienal of the following formula (7):

• the process comprising at least steps of:
• subjecting a (6,6-dialkoxy-4-hexenylidene)triarylphosphorane compound of the following general formula (4):
• Ar3P═CH(CH2)2CH═CHCH(OR1)(OR2) (4)
• wherein Ar may be the same or different at each occurrence and is an aryl group, and R1 and R2 are each independently a monovalent hydrocarbon group having 1 to 18 carbon atoms or together form a divalent hydrocarbon group, R1-R2, having 1 to 18 carbon atoms, to a Wittig reaction with propanal of the following formula (5):
• CH3CH2CHO (5)
• to form a 1,1-dialkoxy-(6Z)-2,6-nonadiene compound of the following general formula (6):
• wherein R1 and R2 are each independently a monovalent hydrocarbon group having 1 to 18 carbon atoms or together form a divalent hydrocarbon group, R1-R2, having 1 to 18 carbon atoms;
• and
• subjecting the 1,1-dialkoxy-(6Z)-2,6-nonadiene compound to hydrolysis to form (2E,6Z)-2,6-nonadienal.