The reaction of tin enolates with nitroalkenes was effectively catalyzed by tetrabutylammonium bromide (Bu4NBr) to give gamma -nitroketones. When the substituted tin enolates at the beta -carbon in the olefinic moiety were used, the diastereoselective addition proceeded through the acyclic transition state. Tetrabutylammonium chloride (Bu4NCl) strongly accelerated the reaction with the cyanoalkene to give the gamma -cyanoketone.