Expanding the Synthetic Scope of Rawal's Diene: Access to Pyran and Pyrazole Derivatives.

The study demonstrates the synthetic versatility of Rawal's diene as a key reagent for the scalable synthesis of MedChem-relevant building blocks. The hetero-Diels-Alder cycloaddition with various ketones based on this reagent provides efficient one-step access to a wide array of substituted dihydropyranones in a scalable manner. These derivatives have shown high synthetic potential for further transformations to tetrahydropyranones and various pyrazoles with an uncommon substitution pattern. All these results demonstrated the effectiveness of Rawal's diene for the synthesis of diverse pyranone-based building blocks and its potential for industrial applications.