2-(Ethoxymethylene)-3-oxobutanoic acid ethyl ester（Cat No.:L041364）, also known as ethyl 2-(ethoxymethylene)-3-oxobutanoate, is an important β-keto ester featuring an ethoxymethylene group at the 2-position and a keto group at the 3-position, along with an ethyl ester moiety. This compound serves as a versatile Michael acceptor and enolate precursor in organic synthesis, especially in the construction of heterocycles and natural product analogs. Its conjugated system allows for diverse nucleophilic additions and cyclization reactions. It is frequently used in multicomponent reactions and synthesis of pharmaceuticals, agrochemicals, and functionalized intermediates due to its reactive functionalities.