Cation–anion confined hydrogen-bonding catalysis strategy for ring-closing C–O/O–H metathesis of alkoxy alcohols under metal-free conditions

Abstract

Cation–anion confined hydrogen-bonding-catalyzed ring-closing C–O/O–H metathesis of alkoxy alcohols to O-heterocycles is realized over OH-functionalized ionic liquids under metal-free and mild conditions (≥70 °C).

Hydrogen Bond Promoted Methoxycarbonylation of Pentanediamine to Biobased Dicarbamate by Accelerating Proton Transfer

“…In the two-step pathway, a nucleophilic attack on the carbonyl carbon atom occurs first, generating a zwitterionic intermediate that collapses into an amide upon alcohol elimination . In the concerted pathway, the proton transfer and elimination of alcohol occur simultaneously without the participation of the carbonyl of ester. − Fortunately, proton transfer and elimination are crucial steps in both mechanisms; thus, the reaction may be accelerated by facilitating proton shuttling. − Hydrogen bonding is pivotal in catalysis, facilitating chemical transformations, including the carbonylation of amines with DMC. − Therefore, the development of a green, efficient, metal-free catalytic system that uses hydrogen bonding is essential for PDC synthesis.…”