Oleic acid cross-metathesis

It has been noted in a recent review that 4 successfully catalyses the cross-metathesis reactions of methyl oleate 1 or oleic acid with ethene see [1]... 

Derivatives of oleic acid that imdergo cross-metathesis with simple olefins are listed in Table 9.4, while Table 9.5 gives some examples of cross-metathesis reactions of simple olefins with other functional olefins. Such cross-metathesis reactions may provide useful routes to speciality chemicals such as synthetic perfumes, insect pheromones (Crisp 1988), prostaglandin intermediates (Dalcanale 1985), etc. (see Mol 1982, 1991). Of special interest are ethenolysis reactions, which allow the synthesis of compoimds with terminal double bonds. Ethenolysis (and cross-metathesis with lower olefins) has been investigated extensively for... 

Table 9.4 Examples of cross-metathesis reactions of oleic acid and its derivatives with simple olefins... 

Cross-metathesis of erucic acid, CH3(CH2)7CH=CH(CH2)nCOOH, with excess oct-4-ene (Hummel 1975a) and of oleic acid with excess hex-2-ene (Hummel 1971) has been observed, although only the hydrocarbon metathesis product has been identified. 

The housefly (Musca domestica) uses the hydrocarbon (Z)-9-tricosene (318 in Scheme 58) as the major component of its sex pheromone. Simple syntheses involve Wittig coupling 153, 154) or alkylation of a terminal alkyne and subsequent reduction 155, 156) to afford the desired Z-isomer in ca. 95% purity. Erucic acid 157, 158) or oleic acid 159, 160) have served as starting material of known Z stereochemistry. The transition metal-catalyzed olefin cross-metathesis reaction has been applied by Rossi 161) to synthesize (318) as a mixture of /Z-isomers together with the other possible Cis and C28 olefins (Scheme 58). 

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