Resumen de Rhodium-Catalyzed C–H Amination: A Case Study of Selectivity in C–H Functionalization Reactions
James B. C. Mack, T. Aaron Bedell, Ryan J. DeLuca, Graham A. B. Hone, Jennifer L. Roizen, Charles T. Cox, Erik J. Sorensen, J. Du Bois
An advanced undergraduate organic chemistry laboratory experiment involving a rhodium-catalyzed intermolecular hydrocarbon C–H oxidation reaction is described. In the initial phase of this lab, students conduct a C–H amination reaction of ethylbenzene and isolate a benzylic amine product. In the second part of the lab, competition experiments are performed to compare the relative rates of C–H insertion with electronically disparate para-substituted ethylbenzene derivatives. Reaction progress is monitored by thin-layer chromatography and the outcome quantitatively assessed using 1H NMR spectroscopy. Data from competition experiments form the basis for a discussion of reaction mechanism including analysis of putative transition structures and relative potential energy barriers for C–H oxidation. Experiments have been designed such that instructors can tailor the level of detail and discussion from introductory to advanced.
