A scaleable and highly regioselective C-4 bromination of 5-substituted oxazoles is described. The use of DMF as solvent played a critical role in significantly improving the C-4/C-2 bromination ratio. The resulting 4-bromooxazoles were shown to be good Suzuki–Miyaura coupling partners with arylboronic acids. Furthermore, a simple and convenient method that employs triethylamine efficiently purged residual levels of palladium and iron to less than 10 ppm.

This study presents a scaleable, highly regioselective C-4 bromination of 5-substituted oxazoles using DMF as solvent, leading to efficient 4-bromooxazoles for Suzuki-Miyaura coupling with arylboronic acids.

Paper

Syntheses of 4,5-Disubstituted Oxazoles via Regioselective C-4 Bromination

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