Optimizing an\nOrganocatalyzed Process in an Undergraduate\nLaboratory: A Solvent Screening

In this undergraduate organic laboratory study, extensive\nsolvent\nscreening was meticulously designed for the optimization of the l-proline-organocatalyzed intermolecular aldol reaction involving\nacetone and <i>p</i>-nitrobenzaldehyde. The experimental\nprocedure entailed selecting specific solvents, analyzing the reaction\ncrude through NMR spectroscopy, and subsequently, purifying the aldol\nadducts to measure their enantiomeric ratios via HPLC provided with\nthe chiral column. Remarkably, this comprehensive investigation was\nefficiently conducted within two concise 2-h laboratory sessions,\ntogether with a 1-h seminar session, rendering it highly suitable\nfor both Bachelor’s and Master’s degree programs. Conducted\nat room temperature, the experiments unveiled significant variations\nin both yields and enantiomeric excess of the aldol products and the\nbyproducts proportions, depending on the solvent of choice. This experiential\nlearning opportunity empowers students to gain practical insights\ninto organocatalyzed transformations, purification techniques, and\nchromatographic analysis, enhancing their proficiency as organic chemists.