The substituents on the olefins apparently have influence on the course of hydrogenation. Other reducible groups such as ethyl ester or amide, halogen, nitro groups were fully compatible with the reaction conditions and remained unaltered. The mechanistic explanation of this reaction remained unclear and it is believed that self coupling of reagent occurs to form the diimide compounds with liberation of hydrogen gas, which is consumed by olefins during reaction. In separate experiments, the compounds with nitrile group and azide were treated under same reaction conditions, we recovered starting materials only, it further enhances the selective reduction of unsaturated carbonyl compounds over nitrile and azides.