Meerwein-Ponndorf-Verley Reductions and Oppenauer Oxidations: An Integrated Approach

Graauw, Cornells F. de; Peters, Joop A.; Bekkum, H. van; Huskens, Jurriaan

doi:10.1055/s-1994-25625

Cited by 506 publications

(284 citation statements)

References 0 publications

Supporting

Mentioning

278

Contrasting

Order By: Relevance

“…Obviously, the excess of benzaldehyde oxidizes the primarily formed lithium alkoxide to ketone 8 in an Oppenauer oxidation process. 16,17 In the classical Oppenauer oxidation, aluminum isopropoxide is used as the catalyst and acetone as the oxidant. Later on, metal ions other than aluminum and various aldehydes and ketones as oxidants have also been reported.…”

Section: Methodsmentioning

confidence: 99%

An interesting sidetrack in the tofisopam synthesis: lithium variant of a stereospecific Oppenauer oxidation

Samu¹,

Simig²,

Halász³

et al. 2015

Arkivoc

View full text Add to dashboard Cite

In the course of the elaboration of a new manufacturing process of anxiolytic drug tofisopam, a stereospecific lithium-catalyzed Oppenauer-type oxidation was observed. Bromine-lithium exchange on the ethylene ketal of 3-(2-bromo-4,5-dimethoxyphenyl)pentan-2-one followed by quenching with 1 equivalent of 3,4-dimethoxybenzaldahyde gave the corresponding alcohols as a mixture of two diastereomeric racemates. On the other hand, when 2.5 equivalents of the aldehyde were applied, only one of the two alcohol diastereomers could be isolated. The lithium alkoxide precursor of the other diastereomeric alcohol, due to the presence of the excess of benzaldehyde as the oxidant, underwent an Oppenauer-type oxidation to give the corresponding ketone.

show abstract

Section: Methodsmentioning

confidence: 99%

An interesting sidetrack in the tofisopam synthesis: lithium variant of a stereospecific Oppenauer oxidation

Samu¹,

Simig²,

Halász³

et al. 2015

Arkivoc

View full text Add to dashboard Cite

show abstract

“…Catalytic systems without transition metals require much higher temperatures for alcohol coupling due to the higher activation energy of dehydrogenation. 65,69,75,80,96,102,103 Next to the different reaction mechanisms proposed (vide infra), dehydrogenation on these catalysts is often proposed to occur by transfer hydrogenation mechanisms like the Meerwein-Ponndorf-Verley reaction (MPV), 104 in which the hydrogen from the reagent alcohol is directly transferred to the unsaturated aldol product. It was shown by Gines and Iglesia 94 that addition of copper to a K-Mg 5 CeO x catalyst resulted in much higher incorporation of deuterium in both reactants and products when the reaction was carried out in the presence of D 2 .…”

Section: Reaction Mechanisms and Thermodynamic Considerationsmentioning

confidence: 99%

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Gabriëls

Hernández

Sels

et al. 2015

Catal. Sci. Technol.

249

233

View full text Add to dashboard Cite

The Guerbet condensation reaction is an alcohol coupling reaction that has been known for more than a century. Because of the increasing availability of bio-based alcohol feedstock, this reaction is of growing importance and interest in terms of value chains of renewable chemical and biofuel production. Due to the specific branching pattern of the alcohol products, the Guerbet reaction has many interesting applications. In comparison to their linear isomers, branched-chain Guerbet alcohols have extremely low melting points and excellent fluidity. This review provides thermodynamic insights and unravels the various mechanistic steps involved. A comprehensive overview of the homogeneous, heterogeneous and combined homogeneous and heterogeneous catalytic systems described in published reports and patents is also given. Technological considerations, challenges and perspectives for the Guerbet chemistry are discussed.

show abstract

“…Similarly, the observed partial oxidations of 4-penten-1-ol, 2,2,2-trifluoro-1-phenylethanol, and benzoin ( Figure 1) under the same catalytic conditions are due to the large negative reduction enthalpies for their oxidation products. [13] On the other hand, the resonance energy gained from the oxidation of cinnamyl alcohol (Table 1, entry 9) shifted the equilibrium towards the a,b-unsaturated aldehyde, resulting in a complete reaction. Furthermore, the dehydrogenation of diols catalyzed by the same iron hydride was successful as the overall oxidation reactions were driven by the favourable formation of lactones from hemiacetal intermediates, which could be generated from the oxidation of one alcohol functionality followed by cyclization (Scheme 4).…”

mentioning

confidence: 99%

Iron‐Catalyzed Oppenauer‐Type Oxidation of Alcohols

et al. 2010

View full text Add to dashboard Cite

A (hydroxycyclopentadienyl)iron dicarbonyl hydride catalyzes the Oppenauer-type oxidation of alcohols with acetone as the hydrogen acceptor. Many functional groups are tolerant to the oxidation conditions. The same complex also catalyzes the dehydrogenation of diols to lactones. A mechanism involving the formation of iron-alcohol complexes and their rapid ligand exchange with free alcohols is proposed. The trimethylsilyl groups on the cyclopentadienyl ligand of the catalyst play a critical role in stabilizing the iron hydride and increasing the catalyst lifetime.

show abstract

Meerwein-Ponndorf-Verley Reductions and Oppenauer Oxidations: An Integrated Approach

Cited by 506 publications

References 0 publications

An interesting sidetrack in the tofisopam synthesis: lithium variant of a stereospecific Oppenauer oxidation

An interesting sidetrack in the tofisopam synthesis: lithium variant of a stereospecific Oppenauer oxidation

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Iron‐Catalyzed Oppenauer‐Type Oxidation of Alcohols

Contact Info

Product

Resources

About