Deformylation Reaction by a Nonheme Manganese(III)–Peroxo Complex via Initial Hydrogen‐Atom Abstraction. Issue 37 (8th July 2016)

• Record Type: Journal Article
• Authors: Barman, Prasenjit; Upadhyay, Pranav; Faponle, Abayomi S.; Kumar, Jitendra; Nag, Sayanta Sekhar; Kumar, Devesh; Sastri, Chivukula V.; de Visser, Sam P.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 37(2016)
• Page Start: 11091
• Page End: 11095
• Publication Date: 2016-07-08
• Subjects: biomimetic models -- density functional theory -- enzyme models -- hydrogen-atom abstraction -- reaction mechanisms; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201604412
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Metal–peroxo intermediates are key species in the catalytic cycles of nonheme metalloenzymes, but their chemical properties and reactivity patterns are still poorly understood. The synthesis and characterization of a manganese(III)–peroxo complex with a pentadentate bispidine ligand system and its reactivity with aldehydes was studied. Manganese(III)–peroxo can react through hydrogen‐atom abstraction reactions instead of the commonly proposed nucleophilic addition reaction. Evidence of the mechanism comes from experiments which identify a primary kinetic isotope effect of 5.4 for the deformylation reaction. Computational modeling supports the established mechanism and identifies the origin of the reactivity preference of hydrogen‐atom abstraction over nucleophilic addition. Abstract : Grab the hydrogen first : A combined spectroscopic, kinetic, and computational modeling study gives first evidence of a rate‐determining hydrogen‐atom abstraction reaction for aldehyde deformation reactions by nonheme manganese(III)–peroxo complexes (see picture: Mn brown, C gray, O red, N blue, H white).