Acetyl ketene is primarily used as a reactive intermediate in organic synthesis. It serves as an acylating agent, particularly in the preparation of esters and amides under mild conditions. Due to its high reactivity, it is employed in the synthesis of pharmaceuticals and fine chemicals where selective acylation is required. It is also utilized in the production of β-lactam antibiotics, contributing to the formation of key structural motifs through controlled ring-forming reactions. Its transient nature makes it suitable for in situ applications, minimizing side reactions and improving yield in complex multi-step syntheses.