Modular synthesis of spirocyclic carbonates: unravelling the synergistic interplay of electronic and electrostatic sites on phenolic catalyst.

The enhancement of 3D character in chemical scaffolds has become an unavoidable space and a key component for diverse applications. Herein, we report a simple phenol-derived catalyst with synergistic involvement of electronic and electrostatic sites to access spirocyclic carbonates from spiroepoxy oxindoles and carbon dioxide. The metal-free and co-catalyst free catalytic system demonstrates excellent activity in synthesizing diverse spirocyclic carbonates with good conversions (up to 99%) under ambient reaction conditions. Volumetric and NMR investigations enabled the synergistic role of the key chemical functionalities in the catalyst and elucidated the probable reaction mechanism. The calculated values of different green metrics revealed the suitability and practical applicability of the catalytic system. [ABSTRACT FROM AUTHOR]