Summary The catalytic hydrogenation of trans-dibenzoylethylene under different conditions results in both mono-and dimolecular products, while other unsaturated 1, 4-diketones1 including cis-dibenzoylethylene and the halogen derivatives, undergo largely monomolecular reduction. The striking parallelism between catalytic and zinc combination reductions is shown and is regarded as indicative of a common reaction mechanism.
