P. A. Barr

Decarbonylation dehydration of fatty acids to alkenes in the presence of transition metal complexes

The catalytic decarbonylation of stearic acid into a mixture of heptadecenes has been accomplished by use of a catalyst system comprised of rhodium trichloride (RhCl3) and triphenylphosphine. The isomeric composition of the heptadecenes formed was found, by spectroscopic and chemical methods, to be dependent upon the type of rhodium catalyst employed. Anhydrous RhCl3 produced about the same amount of 2-heptadecene, twice the amount of 3-heptadecene, and about half the amount of 1-heptadecene as hydrated RhCl3. The active catalytic species formed in situ has been identified as the rhodium I complex [(C6H5)3P]2Rh(CO)Cl. A mechanistic pathway to account for the observed decarbonylation products employing the above catalyst is presented.

Oxidation of unsaturated fatty acids with ruthenium and osmium tetroxide

Abstract and SummaryThe oxidation of the alkali metal salts of oleic and undecylenic acid with ruthenium and osmium tetroxides is reported. The oxidants are used in catalytic amounts in conjunction with an excess of the in-expensive cooxidant sodium hypochlorite. Ruthenium tetroxide cleaves the carbon-carbon double bond of potassium oleate, to give pelargonic and gives sebacic acid. With osmium tetroxide, hydroxylation of the double bond of potassium oleate gives a 95% yield oferythro-9,10-dihydroxystearic acid. The osmium tetroxide oxidation of sodium undecylenate results in the formation of 10,11-dihydroxyundecanoic acid and the cleavage product sebacic acid in varying yields.

Epimino derivatives from β-lodoazides

The preparation of the epimino derivatives of oleyl alcohol and methyl oleate by a two-step procedure has been studied. The procedure utilized the addition of iodine azide to the unsaturated compound, followed by reductive cyclization to the aziridine. For the latter step, several hydride-reducing agents and direct hydrogenation over metal catalysts were investigated. Comparison of the various methods studied showed that the best yields of epimino derivatives were obtained with lithium aluminum hydride, whereas direct hydrogenation gave the poorest yield. The reaction of the β-iodoazide adducts with trimethyl phosphite was also investigated and was shown to give rise to the dialkylphosphonoaziridinyl derivative of the starting olefin.