The Staudinger synthesis[1], named after the German chemist Hermann Staudinger, is a method to prepare β-lactams. An imine reacts with a ketene in a formal [2+2]-cycloaddition to give the cyclic amide.
The reaction was discovered in 1907[2] but did not attract much interest until the 1940s, when the structure of penicillin was elucidated. The β-lactam moiety of the first synthetic penicillin was constructed using this cycloaddition,[3] and it remains a valuable tool in synthetic organic chemistry.