Synthesis of Functionalized Benzo[f]pyrazolo[1,5-a][1,3]diazepines via Rh(III)-Catalyzed Cascade Annulation of 5-Amino-1-aryl-pyrazoles with Iodonium Ylides

This study presents a Rh(III)-catalyzed C–H activation/[5 + 2] cyclization strategy for the efficient synthesis of benzo[f]pyrazolo[1,5-a][1,3]diazepines (BPDs) 3. The [Cp*RhCl₂]₂/AgTFA catalytic system enables the one-step construction of azepane-fused polycycles from 5-amino-1-arylpyrazole and iodonium ylides. Expansion to a three-component reaction was achieved by adjusting the catalyst/additive ratio and incorporating alcohol substrates, enabling the synthesis of BPDs 4. It provides a novel route to aromatic amine-based amino acids, offering significant potential for applications in medicinal chemistry and organic synthesis.