Introduction: Selective hydrogenation of olefin bond of conjugated carbonyl compounds in the presence of other function groups is an important task in organic synthesis. As hydrogen 1,2 from gas cylinder is potentially explosive and requires to be used with caution in a special apparatus, search for alternative methods to conventional hydrogenation procedures such as heterogeneous and homogeneous catalytic transfer hydrogenation is still going on. Surprisingly, there are only a few methods available in the literature for effecting the reduction of the olefin in ,-unsaturated carbonyl/nitro molecules. The most common used reagents for the reduction of conjugated carbonyl compounds are palladium assisted hydrogen transfer by ammonium formate, 3 formic acid, Diphenyl sulfide, 5 polystyrene, or potassium formate, Palladium acetate, 8 metal catalyzed reduction by sodium hydrogen telluride, copper nanoparticles, 10 samarium iodide, lithium aluminum hydride with SbCl3, sodium boroacetate, sodium borohydride reduced hydroxy ester, nickel chloride, iridium, ruthenium, silane hydride and Yeast in organic solvent system. Recently, O-mesityl(sulfonyl)hydroxylamine is used for aziridination of simple olefins. It is a versatile class of reagents and has been used for the various functional group transformation, migration of O-Phenylhydroxylamine, N-Unsubstituted Arylsulfilimines, Hydroxy-amine, Hydrazine, and Beckman Rearrangement. Surprisingly, no significant effort has yet been made to utilize this potential reagent for the regio and stereoselective hydrogenation of double bonds of entry 7). The structure was initially assigned by 1 H, C-NMR and HRMS analyses and further confirmed by single crystal X-ray analysis. To test the generality of the procedure, various substates were subjected to the reaction conditions (see table ) and it is concluded that the ease of reduction is sensitive to steric and electronic factor. For example, when cinnamoyl ester (entry 8, Method-A) high yield is obtained, due to two electron withdrawing group on either side. Whereas low chemical yield (<10%) was obtained with -methyl (entry 9, Method-A) or -bromo (entry 10, Method-A) substituent while no desired products were isolated when ,dimethyl (entry 11, Method-A) or ,dimethyl (entry 12, Method-A) substrates were used. Even more interestingly the chemical yields were significantly improved in the presence of catalytic amount of Lewis acid (entries 1 and 5-8, Method-B). In case of ,-dimethyl (entry 11, Method-B) or ,dimethyl (entry 12, Method-B), even increase the catalyst load to 0.5% and prolong reaction time also did not gave the products. The used of triethylamine or DBU is ineffective on the rate of reaction.