Catalytic Reductive Aminolysis of Reducing Sugars: Elucidation of Reaction Mechanism

Abstract

A catalytic reductive aminolysis of reducing monosaccharides into short ethylene diamines (or C 2 diamines) was recently communicated by our group (Pelckmans et al.

Glycolaldehyde as a Bio-Based C2 Platform Chemical: Catalytic Reductive Amination of Vicinal Hydroxyl Aldehydes

“…54 Our group recently demonstrated the important effect of protic (nonaqueous) solvents such as MeOH to mediate intramolecular proton transfer (PT) reactions during the reductive aminolysis of reducing sugars, thereby drastically lowering the energy barrier for the initial formation of enamine IM of glucose with DMA. 26,55 Song et al reported a similar solvent promoting effect in the reductive amination of normal ketones with Ru/C. 56 They found high ketone conversion in protic solvents, whereas low conversion was observed in THF.…”

“…The reaction mechanism described here is to a large extent similar to that proposed for the reaction of DMA with reducing sugars, previously published by our group. 26 The calculated energy values, however, are not directly comparable because in this study geometry optimizations were carried out in the solvent environment, while gas-phase optimizations were previously used.…”

“…To demonstrate the applicability of our bio-based route as a proof of concept, MDEA and BHEDMEDA diester quats (the latter obtained from Pelckmans et al 26 ) were synthesized from the obtained reaction mixtures, formulated into a fabric softener and tested on standardized towels against an industrial TEA standard fabric softener (structure see Figure S13 in Supporting Information) and a blank.…”

Toward Replacing Ethylene Oxide in a Sustainable World: Glycolaldehyde as a Bio‐Based C2 Platform Molecule

“…When the solvent reactant was replaced by N ‐methylethanolamine (MAE) and an aqueous glucose feed was applied in fed‐batch mode, a surprisingly high yield of up to 87 % N , N ′‐bis(2‐hydroxyethyl)‐ N , N ′‐dimethylethylenediamine, also denoted as BHEDMEDA, could be achieved (Scheme 4). Later, a reaction mechanism for the reductive aminolysis of sugars, based on a combined experimental and theoretical study, was proposed by the same group [107] . It involves the formation of a hemi‐aminal between the sugar and the amine, and subsequent dehydration to produce a zwitterionic iminium intermediate, followed by a fast C−C bond cleavage through intramolecular deprotonation and subsequent hydrogenation of the formed unsaturated amine intermediate.…”

Cycloamination strategies for renewable N-heterocycles

“…31 Given the above considerations, urgent attention is needed to develop green and efficient approaches to task-specific azaheterocycles from renewable biomass feedstocks via sustainable chemistry. The employed nitrogen sources can be derived from ammonia, amines/amides pre-prepared by C-N coupling reactions (e.g., reductive amination, aminolysis, and amidation), [32][33][34][35][36] or natural N-reservoirs (e.g., chitin, proteins) for producing amines and derivatives (e.g., glucosamine, N-acetyl-D-glucosamine, amino acids). [37][38][39][40][41] Beginning from the accessible bio-based functional molecules, N-heterocycles can be constructed by C-N and/or C-C bond formation typically via three dominant synthetic routes including intramolecular cyclization, cycloaddition (e.g., aza-Diels-Alder), and multicomponent condensation reactions (Fig.…”