Palladium-catalyzedhydrogenolysis of 4,5-epoxy-2-alkenoates to 5-hydroxy-2-alkenoates was examined, and it was shown that the (Z)-alkenoate with a bulky substituent at C-4 underwent hydrogenolysis with a decrease in the stereospecificity. Mechanistic considerations and steps for improvement of the stereospecificity are also presented.