Base‐Catalysed Hydrogenation of Sulphur‐Containing Aldehydes

Abstract

The present work reports the first selective catalytic hydrogenation of bifunctional compounds containing a carbonyl and sulphur moieties, using hydrogen transfer from alcohols and a basic catalyst. The reaction was performed in batch at 371 K at atmospheric pressure with 3-mercaptopropionaldehyde, thiophene-2-carboxaldehyde, 5-bromothiophene-2-carboxaldehyde and 4-methylthiobenzaldehyde. The only product of reaction was the alcohol, formed with yields > 80%, except with 3-mercaptopropionaldehyde which did not give the alcohol but rather afforded unidentified heavy products. 5-Bromothiophenemethanol was obtained with 100% yield in 3 h. The reaction obeys a mechanism of competitive adsorption of the reactants, and the reaction rates are higher than those reported for supported rhodium catalysts.

Enantioselective reduction of sulfur-containing cyclic imines through biocatalysis

“…For example, the established hydrogenation technology (Pd/C, H 2 ) was found at an early stage not to be suitable due to catalyst poisoning by sulfur 13 , 14 . These results are in accordance with later results by the Figueras group, finding that metals of supported metal catalysts become poisoned by sulfur 15 . The recently developed organocatalytic reduction with Hantzsch esters for imines 16 , 17 also failed to lead the desired transformation due to lack of reactivity (Supplementary Figs.…”

Heterogeneous Catalysis in the Meerwein-Ponndorf-Verley Reduction of Carbonyl Compounds

“…Finally, hydrotalcite-like catalysts have also been successfully used in the MPV reduction of heterocyclic carbonyl compounds [71,72] and sulphur-containing aldehydes [72], which is a substantial advance as sulphur is a major poison for the metal catalysts typically used in the conventional reduction with hydrogen gas. …”

Chemoselective reduction of a nitro group through transfer hydrogenation catalysed by Ru0-nanoparticles stabilized on modified Montmorillonite clay

“…28 However, transfer hydrogenation is advantageous over the traditional hydrogenation reaction in respect of selectivity in which an alcohol like isopropanol, considered as one of the green solvents, acts as solvent as well as the source of hydrogen and the reaction takes place at atmospheric pressure and relatively low temperature. 19,[27][28][29][30] Moreover, the co-production of acetone in the reaction is also a useful chemical and its production is energetically more economical than the commercial 'cumene peroxide' process, which requires high pressure (30 bar) and temperature (250 °C) and is also associated with distillation. 31 The co-produced acetone can be easily isolated by distillation, which makes the whole process 'green'.…”