Homogeneous and heterogeneous catalytic (dehydrogenative) oxidation of oleochemical 1,2-diols to α-hydroxyketones

Abstract

The preparation of alpha-hydroxyketones derived from fatty acid derivatives has been reported under homogeneous and heterogeneous conditions.

Valorization of Methyl Azelaaldehydate – A Vegetable Oil Based Platform Molecule for the Synthesis of Monomers through Stetter Reaction

“…The epoxide was then hydrolyzed, giving methyl 9,10‐dihydroxystearate 3 in 90 % isolated yield. This diol was selectively oxidized using a Pd(OAc) 2 /neocuproine complex under oxygen atmosphere to give α‐hydroxyketone 4 with 80 % yield . Alternatively, it can also be prepared by dehydrogenation of diol 3 using Ru/C with the removal of hydrogen under vacuum .…”

“…This diol was selectively oxidized using a Pd(OAc) 2 /neocuproine complex under oxygen atmosphere to give α‐hydroxyketone 4 with 80 % yield . Alternatively, it can also be prepared by dehydrogenation of diol 3 using Ru/C with the removal of hydrogen under vacuum . Finally, the cleavage of 4 through NHC‐catalysed retro‐benzoin process gave aldehydes 5 and 6 under reactive distillation conditions, with 85 and 71 % yields, respectively …”

Robust Organocatalysts for the Cleavage of Vegetable Oil Derivatives to Aldehydes through Retrobenzoin Condensation

“…The scope of the cleavage of α‐hydroxyketones derived from vegetable oils was investigated next by using the previously optimized conditions (Table ). These fatty α‐hydroxyketones were prepared from the corresponding diols, either by oxidation using a homogeneous palladium‐neocuproine complex or by dehydrogenation using a heterogeneous ruthenium catalyst . Symmetrical α‐hydroxyketones 4 and 5 , derived from self‐metathesis products of methyl oleate, gave nonanal 2 and methyl azelaaldehydate 3 with 88 and 80 % isolated yields, respectively (Table , entries 1–2).…”

Phosphinous Acid Platinum Complex as Robust Catalyst for Oxidation: Comparison with Palladium and Mechanistic Investigations

“…Since the oxidation of 1,2‐ or 1,3‐ diols into α‐ or β‐hydroxy ketones respectively is particularly challenging owing to potential metal chelation or competitive reaction,, we focused our efforts on this last challenge. Although some efficient and selective catalytic systems have been proposed to this end,, , it should be noted that most of them are based on the use of palladium in combination with nitrogen ligands,, , rather than oxidation‐sensitive phosphine‐type ligand. To our delight, our method allowed the totally selective oxidation of such substrates in good to excellent yields as evidenced by the compounds 3i (89 %) and 3j (68 %).…”