Hydrogenation of sorbic acid in ethyl acetate with [RhCl(PPh3)(3)] was studied and compared to the hydrogenation of its K-salt in water catalyzed by [RhCl(mtppms)(3)]. Aqueous biphasic hydrogenation of sorbic acid with [RhCl(mtppms)(3)] as catalyst proceeded faster and more selectively than that in homogeneous solutions and afforded trans-hex-2-enoic acid with 80% selectivity.