Novel porous organocatalysts for cycloaddition of CO₂and epoxides

Abstract

Three classes of organosilicas (DMO, OMOs and PMOs) containing multi-hydroxyl bis-quaternary ammonium iodide were tested in the cycloaddition of CO2 and epoxides. OMO with two hydroxyl groups was the most active, with good stable and reusability.

Structural Design of Mn-Metal–Organic Frameworks toward Highly Efficient Solvent-Free Cycloaddition of CO2

“…On the basis of previous reports and the reaction results, , we proposed the mechanism of the cycloaddition of CO 2 to epoxides with 1 and 2 / 3 as catalyst in Figure . The oxygen atom in the epoxide, as a Lewis base, combines with the Lewis acidic Mn 2+ sites to form an intermediate, which is attacked by nucleophilic Br – in TBAB on the β-carbon of the substrate with a ring-opening process.…”