Ru-catalyzed Transfer Hydrogenation Research Articles

General and selective homogeneous Ru-catalyzed transfer hydrogenation, deuteration, and methylation of functional compounds using methanol

Catalytic valorization of methanol in organic synthesis and energy technologies is interesting and important for both fundamental research and industrial applications. In particular, its utilization as hydrogen, deuterium and methyl sources for selective reduction and deuteration reactions as well as to access N-methylated products is highly desirable and can be considered as a potential methodology for the amplification of transfer hydrogenation and C1 chemistry. Here, we report homogeneous Ru-MACHO complex catalyzed transfer hydrogenation of different functionalized compounds such as ketones, aldehydes, alkynes, alkenes, imines, azobenzenes, and nitro compounds as well as deoxygenation of N-oxide derivatives employing methanol as an affordable hydrogen donor and solvent. This Ru-based strategy has been proven to be very convenient for the deuteration process to synthesize advanced deuterium-labelled compounds, including the gram-scale synthesis of deuterated pharmaceuticals such as d-Cloperastine, d-Buclizine, d-Diphendyarmine, d-Modafinil, and d-Adrafinil using CD3OD. In addition, the application of methanol as a C1 source for the preparation of N-methylated products is showcased. Finally, kinetic and mechanistic investigations for this Ru-catalyzed transfer hydrogenation and deuteration protocols have been performed.

C3-Alkylation of Indoles via Ru-Catalyzed Transfer Hydrogenation and Borrowing Hydrogen Approaches

C3-Alkylation of Indoles via Ru-Catalyzed Transfer Hydrogenation and Borrowing Hydrogen Approaches

Enantioselective synthesis of GNE-6688, a potent and selective inhibitor of interleukin-2 inducible T-cell kinase (ITK)

An enantioselective synthesis of the previously-disclosed ITK inhibitor GNE-6688 is described. Synthesis of the nitropyrazole fragment is highlighted by a Ru-catalyzed transfer hydrogenation using the Wills tethered ligand system. Synthesis of the pyrazole carboxylic acid fragment features an allylboration catalyzed by a chiral diol-SnCl4 complex, followed by a highly diastereoselective directed cyclopropanation.

Design, Synthesis, and Application of NNN Pincer Ligands Possessing a Remote Hydroxyl Group for Ruthenium-Catalyzed Transfer Hydrogenation of Ketones

A new family of pyridyl-based NNN pincer ligands bearing a remote pendent OH group were developed. Considerable acceleration effects on the activity of Ru-catalyzed transfer hydrogenation of ketones were imparted by the pendent OH group, and importantly, introducing a CH2OH group to the 4′-position of the pyrazolyl moiety is an appropriate choice. The results present a general strategy for exploring bifunctional ligands to construct effective catalysts.

N,P]-pyrrole-phosphine ligand: An efficient and robust ligand for Ru-catalyzed transfer hydrogenation microwave-assisted reactions

A pyrrolyl-containing [N-P]-ligand (L1) and [Ru] were evaluated as catalytic system in transfer hydrogenation reaction of ketones. A comparison between microwave irradiation vs conventional heating conditions indicates that MW can be successfully used as energy source, improving the reaction time. The L1/Ru(II) proved to be an active, efficient and robust catalytic system. The scope of this catalytic system was evaluated using a diversity of substrates that include electron-withdrawing and electron-donor groups achieving a range of 65 to 95% conversion. Moreover, the catalytic system showed good activity even with highly sterically hindered ketones.

Synthesis of cyclic imides from nitriles and diols using hydrogen transfer as a substrate-activating strategy.

An atom-economical and versatile method for the synthesis of cyclic imides from nitriles and diols was developed. The method utilizes a Ru-catalyzed transfer-hydrogenation reaction in which the substrates, diols, and nitriles are simultaneously activated into lactones and amines in a redox-neutral manner to afford the corresponding cyclic imides with evolution of H2 gas as the sole byproduct. This operationally simple and catalytic synthetic method provides a sustainable and easily accessible route to cyclic imides.

Diaryl Ketone Synthesis by [RuHCl(CO)(PPh3)3]-catalyzed Coupling Reaction of Arylboronic Acids with Aryl Aldehydes

Abstract [RuHCl(CO)(PPh3)3] was found to be an efficient catalyst for the coupling reaction of arylboronic acids with aryl aldehydes. The reaction proceeded smoothly in the presence of K2CO3 and H2O to give diaryl ketones in good yields. Diaryl ketones were obtained from primarily formed alcohols via Ru-catalyzed transfer hydrogenation reaction.

Carbohydrate-based pseudo-dipeptides: new ligands for the highly enantioselective Ru-catalyzed transfer hydrogenation reaction

Ruthenium-complexes of novel carbohydrate based pseudo-dipeptide ligands effectively and selectively catalyze the reduction of a broad range of aryl-alkyl ketones under ATH conditions. Excellent enantioselectivities (>99% ee) are obtained using aminosugars as the sole source of chirality.

A Practical Synthesis of (S)-Cyclopent-2-enol

Corrected by: A Practical Synthesis of (S)-Cyclopent-2-enolSynlett 2010; 2010(05): 840-840DOI: 10.1055/s-0029-1219555

Facile synthesis of a mesoporous silica-supported catalyst for Ru-catalyzed transfer hydrogenation of ketones

A convenient method for preparation of a mesoporous silica-supported chiral catalyst by postgrafting a homogeneous catalyst on SBA-15 was developed and its application in the asymmetric transfer hydrogenation of aromatic ketones was investigated.