Green Carbonyl Condensation Reactions Demonstrating Solvent and Organocatalyst Recyclability

A procedure is described where students undertake consecutive Knoevenagel and Michael reactions in one pot under green conditions to obtain a condensation product. Fundamental lecture principles of carbonyl group reactivity and catalysis are underscored. The recyclable nature of both an environmentally benign solvent (polyethylene glycol) and organocatalyst (proline) is demonstrated, in conjunction with other sustainability features. This semimicroscale reaction is conveniently performed during a 3.5 h period either toward the end of an introductory organic course or within an upper-level mechanistic laboratory.