Cycloaddition reactions of cumulenes. Part III. Diketen as an allene-like system in the reaction with an azomethine oxide

Abstract

The synthesis of 2-acetoacetyl-5-benzoyl-1-phenylpyrrolidin-3-one (5) from diketen and C-benzoyl-N-phenyl-azomethine oxide (benzoylmethyleneaniline N-oxide) is described. Its structure was elucidated by spectrometric methods, and its main mass spectral fragmentation path is presented. The formation of product (5) by a cycloaddition reaction followed by intramolecular rearrangement and acetoacetylation is discussed.