Modular Approach for Photoinduced Cycloaddition Enabling the Synthesis of Diverse Bioactive Oxazoles

The synthesis of bioactive oxazoles is often inefficient,
and the
reported methods remain largely unexplored for complex derivatives.
To circumvent this issue, we have utilized a metal-free, photomediated
[3 + 2] cycloaddition reaction between diazo compounds and nitriles,
leading to a step- and reagent-economical synthesis of bioactive oxazoles.
These exciting developments guided us in the efficient synthesis of
oxazole-based natural products like annuloline, alkaloids like pimprinethine,
labradorin 2, and oxazole-containing pharmaceuticals such as oxaprozin.
Utilizing this approach, we have also demonstrated efficient synthesis
of deuterium-labeled and heterocyclic-based oxazoles.