Resumen de Synthesis of Substituted Butenolides. An Undergraduate Organic Laboratory Experiment Utilizing Two 3-Step Preparatory Sequences

Geraldine Maheut, Liang Liao, Jean Marie Catel, Paul-Alain Jaffrès, Didier Villemin

• The synthesis of substituted butenolide is reported in two 3-step sequences that illustrate five basic organic reactions (alkyne hydration, Knoevenagel condensation, lactonization, aldolization-type reaction, and hydration of nitrile). The molecules were designed to have pedagogical interest for IR and NMR spectroscopy, such as the observation of the diastereotopic effect. Molecular modeling calculations and a proton-proton homonuclear decoupling experiment for one of these compounds were carried out to demonstrate the presence of a diastereotopic effect.