A Green Synthetic Approach towards Polyarylated Oxazoles via Iodine-Catalyzed One-Pot sp3 C-H Functionalization in Water: From Natural Product Synthesis To Photophysical Studies

A 'green' methodology for the convenient synthesis of specific regioisomers of polysubstituted oxazoles through iodine catalyzed, water-mediated, aerobic oxidative C(sp(3))-H functionalization of primary amines has been developed. This mild and regioselective domino procedure does not require toxic peroxides, transition metals and organic solvents. The versatility of this methodology was demonstrated by preparing a natural product, texaline. It is also scalable and has a wide substrate scope. This methodology opens up a simple avenue for the synthesis of polyarylated oxazoles from various readily available amines as well as 1,2-diketones and acyloins (alpha-hydroxyl ketones) in moderate to excellent yields. Furthermore, these highly substituted oxazole molecules showed excellent fluorescence properties and thus have enormous potential to be a new type of fluorescent probe for use in medicinal applications and materials science.