Exploring Green Chemistry With Aerobic Hypervalent Iodine Catalysis

The demand for sustainable synthetic methods has motivated the development of a myriad of strategies for substrate oxidation chemistry that reflect the goals of green chemistry. Here we present a two-part laboratory module that provides undergraduate chemistry students hands-on experience with the concepts of sustainable chemistry in the context of C-N bond-forming chemistry. First, students perform a traditional Pd-catalyzed C-N cross-coupling reaction between an aryl halide and an amine (i.e., C-X/N-H coupling). In the second part, students investigate a hypervalent iodine-catalyzed reaction that uses O-2 as a terminal oxidant for direct C-H/N-H coupling. On the basis of these two methods for accessing the same arylated amine product, students evaluate aspects of sustainability qualitatively by discussing the 12 Principles of Green Chemistry and quantitatively via green chemistry metric pentagons. These investigations highlight the complex balance of variables that must be considered when evaluating the sustainability of chemical processes. Through these activities, students explore the concepts of aerobic oxidation, hypervalency, green chemistry, and organocatalysis, while enforcing laboratory skills such as Schlenk-line technique, gas handling, and NMR spectroscopy.