Fe(TAML)Li/(diacetoxyiodo)benzene‐Mediated Oxidation of Alcohols: Evidence for Mild and Selective C–O and C–C Oxidative Cleavage in Lignin Model Transformations

Abstract

A novel combination of Fe(TAML)Li and (diacetoxyiodo)benzene for the oxidation of primary and secondary alcohols at 25 °C in acetone is reported. In view of the interesting ability of this system to selectively cleave specific types of C–C bonds of elaborated alcohols, the application of this novel combination to the oxidative cleavage of lignin model molecules was investigated. Considering the numerous supported versions of the oxidant as well as the mild conditions employed, the developed methodology appears to be a promising lignin depolymerization strategy.

Iron-catalysed oxidative cleavage of lignin and β-O-4 lignin model compounds with peroxides in DMSO

“…14 Recently, Andrioletti and co-workers have reported the cleavage of a monolignol β-O-4 model compound with Fe(TAML)Li as catalyst and DAIB as oxidant (Scheme 1). 15 The corresponding ketone was obtained as the main product in 31%, while the cleavage products veratraldehyde and veratric acid were formed in 15% and 3% yield, respectively.…”

“…15 We decided to focus our attention on for iron complexes containing inexpensive nitrogen ligands. Along these lines, a report by Cahiez and co-workers on alkylations of aromatic Grignard reagents with [(FeCl 3 ) 2 (TMEDA) 3 ] as catalyst caught our attention, 16 and we wondered if this type of catalyst would also be suitable for oxidation reactions.…”

Oxidized Lignin Depolymerization using Formate Ionic Liquid as Catalyst and Solvent

“…Secondly, several oxidation catalysts, including TEMPO′/Cu(OAc) 2 , TEMPO′/NaClO, TEMPO′/Fe(NO 3 ) 3 , TEMPO′/NaNO 2 , and Fe(TAML)Li/(diacetoxyiodo)benzene (DAIB), were chosen to oxidize model compounds and lignin to investigate optimal oxidation catalyst.…”

Review on Catalytic Cleavage of C–C Inter-unit Linkages in Lignin Model Compounds: Towards Lignin Depolymerisation

“…Napoly et al reported Fe (TAML) Li (Fe tetraamido macrocyclic complex) catalyst for the oxidative cleavage of C α -C β bond in β-O-4 model compound 1 using (diacetoxyiodo) benzene (DAIB) as the oxidant at 25 °C (Fig. 15) [74].…”

“…Though the exact role of water in increasing the selectivity of C α -C β bond cleavage is not clearly understood. They have extended this methodology for the cleavage of β-1 linkage as well in a lignin model compound similar to 8 [74].…”