An approach to synthesis of 2‐, 4‐, and 5‐bromooxazoles is described. The method was optimized, and its scope was extended to all three isomeric parents, as well as various alkyl‐ and aryl‐substituted bromooxazoles. It was found that direct regiocontrolled lithiation followed by reaction with electrophilic bromine source was common for all substrates and led exclusively to the target substituted 2‐, 4‐ and 5‐bromooxazoles on multigram scale. The utility of the multipurpose building blocks obtained in this work was demonstrated in the Suzuki–Miyaura cross‐coupling reaction under parallel synthesis conditions.
A method for the synthesis of indazoles was developed which involves a copper(ii) acetate catalysed reaction of 2-formylboronic acids with diazadicaboxylates followed by acid or base induced ring closure.
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