Diethyl 2-oxopent-3-ynedioate: Synthesis and first cyclizations of a novel, reactive alkyne

Article abstract of DOI:10.1055/s-1995-3898

Diethyl 2-oxopent-3-ynedioate (3), the carbonyl homologue of diethyl acetylenedicarboxylate, is prepared by thermolysis of bis(ethoxalyl)methylenetriphenylphosphorane (2) and is found to be a reactive building block. Diels-Alder reaction of its alkyne unit with 1,3-diphenylisobenzofuran affords the cycloadduct 4, whereas reaction with binucleophiles such as ortho-XH-anilines (X = O,NH,S) leads to the incorporation of the oxoalkyne C₃ -segment into the heterocycles 5-7.