An organocatalyzed asymmetricaldolreaction of α-keto amides was developed. An N-terminal 4-trans-siloxyproline-based tripeptide with an l-tert-leucine unit adjacent to the 4-trans-siloxyproline residue was used to catalyze the reaction between various α-keto amides and acetone, to produce the corresponding aldol adducts with up to 99% yield and 91% ee.