1-Hydroxy-2,5-hexanedione, obtained in good yield from renewable 5-hydroxymethylfurfural, is a versatile building block for a variety of new compounds.

An efficient strategy for the conversion of biomass derived 5-hydroxymethylfurfural (HMF) into 2-hydroxy-3-methylcyclopent-2-enone (MCP) by an intramolecular aldol condensation of 1-hydroxyhexane-2,5-dione (HHD) has been developed. Further transformations of MCP towards the diol, enol acetate, levulinic acid and N-heterocyclic compounds are also reported.

Herein, we report on the use of the iron pincer complex Iron‐MACHO‐BH, in the base‐free transfer hydrogenation of esters with EtOH as a hydrogen source. More than 20 substrates including aromatic and aliphatic esters and lactones were reduced affording the desired primary alcohols and diols with moderate to excellent isolated yields. It is also possible to reduce polyesters to the diols with this method, enabling a novel way of plastic recycling. Reduction of the renewable substrate methyl levulinate proceeds to form 1,4‐pentanediol directly. The yields are largely governed by the equilibrium between the alcohol and the ethyl ester.

An efficient two‐step synthesis for the conversion of biomass‐derived 5‐hydroxymethyl‐furfural (HMF) to a variety of N‐substituted 2‐hydroxymethyl‐5‐methylpyrroles was developed. In the first step, 1‐hydroxyhexane‐2,5‐dione (HHD) was obtained by hydrogenation of HMF and thereafter used in a Paal–Knorr reaction with a range of amines in the absence of catalyst at room temperature. The reaction could potentially be used as a click reaction.