An efficient synthesis of α-amino ketones is developed using the umpolung strategy. Umpoled enolates such as N-alkenoxypyridinium salts react smoothly with diverse amines to give α-amino ketones via an S_N2′ pathway. This umpolung strategy overcomes the drawbacks of traditional methods such as the need for prefunctionalized ketone derivatives. Our method also offers good chemical yields and high functional group tolerance.