Cu-catalysed pyrazole synthesis in continuous flow†
Abstract
The synthesis of 1,4-disubstituted pyrazoles via the cycloaddition reaction of sydnones and terminal alkynes has been achieved employing silica-supported copper catalysts. Furthermore, this methodology has been successfully implemented in continuous flow conditions using prepacked stainless steel cartridges containing the solid-supported copper promoter. Finally, we demonstrate that this synthetic procedure can be successfully scaled up to produce practically useful amounts of pyrazole products within 2–5 hours.
- This article is part of the themed collections: Celebrating our 2018 prize and award winners and Catalysis in Flow Chemistry