Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes.

ABSTRACT: Catalytic hydrogenation of cyclic carbonates to diols and methanol was achieved using a molecular catalyst based on earth-abundant manganese. The complex [Mn(CO)2 (Br)[HN(C2 H4 Pi Pr2 )2 ] 1 comprising commercially available MACHO ligand is an effective pre-catalyst operating under relatively mild conditions (T=120?°C, p(H2 )=30-60?bar). Upon activation with NaOt Bu, the formation of coordinatively unsaturated complex [Mn(CO)2 [N(C2 H4 Pi Pr2 )2 )] 5 was spectroscopically verified, which confirmed a kinetically competent intermediate. With the pre-activated complex, turnover numbers up to 620 and 400 were achieved for the formation of the diol and methanol, respectively. Stoichiometric reactions under catalytically relevant conditions provide insight into the stepwise reduction form the CO2 level in carbonates to methanol as final product.

SUBMITTER: Kaithal A

PROVIDER: S-EPMC6221167 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes.

Kaithal Akash A Hölscher Markus M Leitner Walter W

Angewandte Chemie (International ed. in English) 20180912 41

Catalytic hydrogenation of cyclic carbonates to diols and methanol was achieved using a molecular catalyst based on earth-abundant manganese. The complex [Mn(CO)2 (Br)[HN(C2 H4 Pi Pr2 )2 ] 1 comprising commercially available MACHO ligand is an effective pre-catalyst operating under relatively mild conditions (T=120 °C, p(H2 )=30-60 bar). Upon activation with NaOt Bu, the formation of coordinatively unsaturate ...[more]

PMID: 30134081

Similar Datasets

Catalytic enantioselective intramolecular hydroamination of alkenes using chiral aprotic cyclic urea ligand on manganese (II).

Project description:Asymmetric catalysis for enantioselective intramolecular hydroamination of alkenes is a critical method in the construction of enantioenriched nitrogen-containing rings, often prevalent in biologically active compounds and natural products. Herein, we demonstrate a facile enantioselective intramolecular hydroamination of alkenes for the synthesis of chiral pyrrolidine, piperidine, and indoline moieties, using a manganese (II) chiral aprotic cyclic urea catalyst. The cyclic ligand hinders the inversion of the N atom of the urea and effectively discriminate between the enantiomers of substrates. High-resolution mass spectrometry, deuterium labeling experiments, and molecular orbital energy analysis clearly reveal the intermediates and mechanism of the transformation. As a key step, oxygen coordination by chiral aprotic urea presents a robust control over the asymmetric intra-HA reaction through the involvement of a convergent assembly of two vital intermediates (Mn-N and C-Mn-Br), providing access to chiral cyclic amine systems in high yields with excellent enantioselectivity.

| S-EPMC11300822 | biostudies-literature

Nitrene-Mediated C-H Oxygenation: Catalytic Enantioselective Formation of Five-Membered Cyclic Organic Carbonates.

Project description:The synthesis of non-racemic 5-membered cyclic carbonates from abundant alcohols is reported. Conversion of the alcohol into an azanyl carbonate is followed by a chiral-at-ruthenium catalyzed cyclization to provide chiral cyclic carbonates in yields of up to 95 % and with up to 99 % ee. This new synthetic method is proposed to proceed through a nitrene-mediated intramolecular C(sp3 )-H oxygenation which includes an unusual 1,7-hydrogen atom transfer within a ruthenium nitrene intermediate. The method is applicable to the synthesis of non-racemic chiral mono-, di- and trisubstituted cyclic alkylene carbonates.

| S-EPMC9827974 | biostudies-literature

A Neutral Heteroatomic Zintl Cluster for the Catalytic Hydrogenation of Cyclic Alkenes.

Project description:We report on the synthesis of an alkane-soluble Zintl cluster, [η4-Ge9(Hyp)3]Rh(COD), that can catalytically hydrogenate cyclic alkenes such as 1,5-cyclooctadiene and cis-cyclooctene. This is the first example of a well-defined Zintl-cluster-based homogeneous catalyst.

| S-EPMC7596751 | biostudies-literature

Non-Pincer-Type Manganese Complexes as Efficient Catalysts for the Hydrogenation of Esters.

Project description:Catalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub-stoichiometric amounts of KOt Bu base.

| S-EPMC5485043 | biostudies-literature

Exploring Oxidation State-Dependent Selectivity in Polymerization of Cyclic Esters and Carbonates with Zinc(II) Complexes.

Project description:Neutral zinc alkoxide complexes show high activity toward the ring-opening polymerization of cyclic esters and carbonates, to generate biodegradable plastics applicable in several areas. Herein, we use a ferrocene-chelating heteroscorpionate complex in redox-switchable polymerization reactions, and we show that it is a moderately active catalyst for the ring-opening polymerization of L-lactide, ?-caprolactone, trimethylene carbonate, and ?-valerolactone. Uniquely for this type of catalyst, the oxidized complex has a similar polymerization activity as the corresponding reduced compound, but displays significantly different rates of reaction in the case of trimethylene carbonate and ?-valerolactone. Investigations of the oxidized compound suggest the presence of an organic radical rather than an Fe(III) complex. Electronic structure and density functional theory (DFT) calculations were performed to support the proposed electronic states of the catalytic complex and to help explain the observed reactivity differences. The catalyst was also compared with a monomeric phenoxide complex to show the influence of the phosphine-zinc interaction on catalytic properties.

| S-EPMC6153418 | biostudies-literature

Fischer Carbene Complexes of Iridium(I) for Application in Catalytic Transfer Hydrogenation.

Project description:New examples of the very rare class of iridium(I) Fischer carbene complexes (FCCs) are reported from the facile transmetalation from group 6 FCCs. Postcomplexation modification of either the carbene ligand or the ancillary coligands results in a tunable IrI metal center, for unprecedented application as a (pre)catalyst in a benchmark transfer hydrogenation reaction. The introduction of an aminocarbene ligand with a pendant N-donor moiety capable of hemilabile coordination yielded the best catalytic results with turnover frequencies reaching 445 h-1 and requiring 0.1 mol % catalyst and 0.5 mol % base loading, respectively.

| S-EPMC7311058 | biostudies-literature

Selective Catalytic Synthesis of 1,2- and 8,9-Cyclic Limonene Carbonates as Versatile Building Blocks for Novel Hydroxyurethanes.

Project description:The selective catalytic synthesis of limonene-derived monofunctional cyclic carbonates and their subsequent functionalisation via thiol-ene addition and amine ring-opening is reported. A phosphotungstate polyoxometalate catalyst used for limonene epoxidation in the 1,2-position is shown to also be active in cyclic carbonate synthesis, allowing a two-step, one-pot synthesis without intermittent epoxide isolation. When used in conjunction with a classical halide catalyst, the polyoxometalate increased the rate of carbonation in a synergistic double-activation of both substrates. The cis isomer is shown to be responsible for incomplete conversion and by-product formation in commercial mixtures of 1,2-limomene oxide. Carbonation of 8,9-limonene epoxide furnished the 8,9-limonene carbonate for the first time. Both cyclic carbonates underwent thiol-ene addition reactions to yield linked di-monocarbonates, which can be used in linear non-isocyanate polyurethanes synthesis, as shown by their facile ring-opening with N-hexylamine. Thus, the selective catalytic route to monofunctional limonene carbonates gives straightforward access to monomers for novel bio-based polymers.

| S-EPMC7317810 | biostudies-literature

Efficient Hydrogenation of N-Heterocycles Catalyzed by NNP-Manganese(I) Pincer Complexes at Ambient Temperature.

Project description:Manganese-catalyzed hydrogenation reactions have aroused widespread interest in recent years. Among the catalytic systems described, especially PNP- and NNP-Mn pincer catalysts have been reported for the hydrogenation of aldehydes, ketones, nitriles, aldimines and esters. Furthermore, NNP-Mn pincer compounds are efficient catalysts for the hydrogenolysis of less reactive amides, ureas, carbonates, and carbamates. Herein, the synthesis and application of specific imidazolylaminophosphine ligands and the corresponding Mn pincer complexes are described. These new catalysts have been characterized and studied by a combination of experimental and theoretical investigations, and their catalytic activities have been tested in several hydrogenation reactions with good to excellent performance. Especially, the reduction of N-heterocycles can be performed under very mild conditions.

| S-EPMC10100126 | biostudies-literature

Metal-Ligand Cooperation Facilitates Bond Activation and Catalytic Hydrogenation with Zinc Pincer Complexes.

Project description:A series of PNP zinc pincer complexes capable of bond activation via aromatization/dearomatization metal-ligand cooperation (MLC) were prepared and characterized. Reversible heterolytic N-H and H-H bond activation by MLC is shown, in which hemilability of the phosphorus linkers plays a key role. Utilizing this zinc pincer system, base-free catalytic hydrogenation of imines and ketones is demonstrated. A detailed mechanistic study supported by computation implicates the key role of MLC in facilitating effective catalysis. This approach offers a new strategy for (de)hydrogenation and other catalytic transformations mediated by zinc and other main group metals.

| S-EPMC7453403 | biostudies-literature

Rational Design of a Facially Coordinating P,N,N Ligand for Manganese-Catalysed Enantioselective Hydrogenation of Cyclic Ketones.

Project description:DFT calculations on the full catalytic cycle for manganese catalysed enantioselective hydrogenation of a selection of ketones have been carried out at the PBE0-D3PCM //RI-BP86PCM level. Mn complexes of an enantiomerically pure chiral P,N,N ligand have been found to be most reactive when adopting a facial coordination mode. The use of a new ligand with an ortho-substituted dimethylamino-pyridine motif has been calculated to completely transform the levels of enantioselectivity possible for the hydrogenation of cyclic ketones relative to the first-generation Mn catalysts. In silico evaluation of substrates has been used to identify those likely to be reduced with high enantiomer ratios (er), and others that would exhibit less selectivity; good agreements were then found in experiments. Various cyclic ketones and some acetophenone derivatives were hydrogenated with er's up to 99 : 1.

| S-EPMC10107995 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data