Abstracts from the Top 10 Winners of the Indiana Academy of Science , Science Talent Search Competition 2020 An Efficient and Environmentally Friendly Synthetic Method for Aromatic Amino Acids (original) (raw)

BACKGROUND: Aromatic α-amino acids are important structural units in natural products, pharmaceuticals, agrochemicals, materials, and dyes. Over the course of the past century, considerable efforts have been made to develop methods to synthesize these molecules. Unfortunately, current approaches suffer from the need to use expensive metal species, toxic reagents, surplus and expensive starting materials, or a multi-step synthesis. Consequently, they are not industrially practical processes. METHODS: My research goal was to develop an efficient, economically and ecologically beneficial process to access aromatic α-amino acids. The cross-coupling reaction of an aryl iodide and glycine ester was performed. RESULTS: In this study, the α-arylation of an inexpensive, commercially available glycine ester was achieved with aryl iodides under transition metal-free conditions in the presence of potassium tert-butoxide. This reaction features a broad substrate scope and good functional group compatibility, and thus provides a straightforward synthesis for a wide range of aromatic amino acids. CONCLUSIONS: The experimental results support that this process begins with the formation of an aryl radical ─ generated from the treatment of an aryl iodide with potassium tert-butoxide ─ and yields an aromatic amino acid product ─ formed from the addition of the aryl radical to a glycine derivative. Because of the importance of aromatic α-amino acids in natural products, medicine, and materials, this newly developed process has broad applications in organic, pharmaceutical, and material chemistry research.