Abstract: There is provided an ?-carbonyl alkenyl ester and a preparation method therefor, and the ?-carbonyl alkenyl ester is further used to react with a primary or secondary amine to prepare an amide. The two reactions are combined to develop an amide bond and peptide bond formation method that directly use carboxylic acids and amines as starting materials and allenones as a condensing reagent. The ?-carbonyl alkenyl ester corresponding to an ?-amino acid serves as a peptide synthesis building block and is used in solid phase peptide synthesis. The method is carried out under mild reaction conditions, simple to operate, and has a high yield. Compared with existing amide bond condensation reagents, the allenones have the advantages of being simple to prepare, having good stability, a low molecular weight, not racemizing when activating ?-chiral carboxylic acids, and is a novel amide bond and peptide bond condensing reagent.