Regioselective synthesis of a stereodefined heterocyclic push-pull alkene - H-1 NMR studies and two-dimensional TLC illustrating Z/E isomerization

Abstract

Introducing students to the regioselective synthesis of a stereodefined push-pull alkene from inexpensive chemicals can be facilicated through experiment. In the experiment, preparation of the precursor, such as diethyl mercaptosuccinate from mercaptosuccinic acid and ethanol in toluene as a cosolvent, demonstrates the educational significance of binary and tertiary azeotropes in practical organic synthesis. The utility of 1H NMR spectroscopy is illustrated as a tool to identify the configurational isomers and to study the stereodynamic behavior of the isolated heterocyclic product.