Synthesis of pyrazolone fused benzodiazepines via Rh(iii)-catalyzed [4 + 3] annulation of 1-phenylpyrazolidinones with propargyl alcohols

An efficient synthesis of pyrazolone fused benzodiazepines through an unprecedented regioselective [4 + 3] annulation of 1-phenylpyrazolidinones with propargyl alcohols via Rh(iii)-catalyzed redox-neutral C–H/N–H/C–O bond activation is presented.