Mechanistic insight into the self-coupling of 5-hydroxymethyl furfural to C₁₂ fuel intermediate catalyzed by ionic liquids

Abstract

The self-coupling of HMF to DHMF catalyzed by ionic liquids has been rationalized well by performing DFT calculations.

Adaptive carbonyl umpolung involving a carbanionic carbene Breslow intermediate: an alternative mechanism for NHC-mediated organocatalysis

“…14,[39][40][41][42] The subsequent stage of carbonyl umpolung may proceed by base-assisted proton transfer in II, leading to the formation of Breslow intermediate III. 4,43,44 The structure of NHC may influence the energy of the reaction intermediates and transition states. 45 The overall process of NHC-mediated condensation of furfural to furoin is exothermic (Table S3 †) and considered reversible.…”

Synthesis of amine derivatives from furoin and furil over a Ru/Al2O3 catalyst

“…7 FF and HMF can self-condense towards 5,5′-dihydroxymethylfuroin (DHMF) derivatives using NHC organocatalysts. 8 The reaction mechanism operates via umpolung condensation as proposed by Breslow. 9 In particular, benz-imidazolium (bim) salts with one/two long-chain aliphatic substituents at the N-atoms in the imidazole ring are active catalysts for the reaction.…”