Chemo- and diastereoselective synthesis of spiro-iminoindoline-pyrazolines as potential antioxidant reagents

Abstract

The construction of spiro-iminoindoline-pyrazolines from readily available starting materials has garnered significant interest within the synthetic chemistry community. Herein, we report a chemo- and diastereoselective (2 + 3) and three-component formal (1 + 1 + 3) cascade cyclization strategy for their synthesis, demonstrating unprecedented C=C chemoselectivity of nitrile imines toward α,β-unsaturated imines. This method delivers multifunctionalized products efficiently under mild conditions. Furthermore, preliminary antioxidant screening using the DPPH radical scavenging assay highlights their potential bioactivity.