Patent ID: 6781004
Filing Date: 2004-08-24
Classification: C07C

Abstract:
A process for the preparation of cis-6-hexadecenoic acid of the formula I, which comprises reactinga1) a triphenylphosphonium salt of the formula II, R1OOCâ€”(CH2)5â€”P(R2)3+Xâˆ’â€ƒâ€ƒII â€ƒin which the substituents, independently of one another, have the following meanings: R1 is C1-Cl2-alkyl, aryl; R2 is aryl and Xâˆ’ is an anion equivalent of an inorganic or organic acid with decanal of the formula III H3Câ€”(CH2)8â€”CH&boxH;Oâ€ƒâ€ƒIII â€ƒin a Wittig reaction, or reacting a2) a triphenylphosphonium salt of the formula IV, H3Câ€”(CH2)9â€”P(R2)3+Xâˆ’â€ƒâ€ƒIV â€ƒin which the substituents R2 and Xâˆ’, independently of one another, have the meanings given above: with an aldehyde of the formula V, R1OOCâ€”(CH2)4â€”CH&boxH;Oâ€ƒâ€ƒV â€ƒin which R1 has the meaning given above, in a Wittig reaction and b) saponifying the ester, formed by process step a1) or a2) of the formula VI, â€ƒin which R1 has the meaning given above, wherein the Wittig reaction in process step a) takes place with a Z/E selectivity greater than 90/10.