Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Lithium Dihydropyridine Dehydrogenation Catalysis: A Group 1 Approach to the Cyclization of Diamine Boranes.

ABSTRACT: In reactions restricted previously to a ruthenium catalyst, a 1-lithium-2-alkyl-1,2-dihydropyridine complex is shown to be a competitive alternative dehydrogenation catalyst for the transformation of diamine boranes into cyclic 1,3,2-diazaborolidines, which can in turn be smoothly arylated in good yields. This study established the conditions and solvent dependence of the catalysis through NMR monitoring, with mechanistic insight provided by NMR (including DOSY) experiments and X-ray crystallographic studies of several model lithio intermediates.

SUBMITTER: McLellan R

PROVIDER: S-EPMC5396369 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Lithium Dihydropyridine Dehydrogenation Catalysis: A Group 1 Approach to the Cyclization of Diamine Boranes.

McLellan Ross R Kennedy Alan R AR Orr Samantha A SA Robertson Stuart D SD Mulvey Robert E RE

Angewandte Chemie (International ed. in English) 20161221 4

In reactions restricted previously to a ruthenium catalyst, a 1-lithium-2-alkyl-1,2-dihydropyridine complex is shown to be a competitive alternative dehydrogenation catalyst for the transformation of diamine boranes into cyclic 1,3,2-diazaborolidines, which can in turn be smoothly arylated in good yields. This study established the conditions and solvent dependence of the catalysis through NMR monitoring, with mechanistic insight provided by NMR (including DOSY) experiments and X-ray crystallogr ...[more]

PMID: 28000994

Similar Datasets

Isolated Rh atoms in dehydrogenation catalysis.

Project description:Isolated active sites have great potential to be highly efficient and stable in heterogeneous catalysis, while enabling low costs due to the low transition metal content. Herein, we present results on the synthesis, first catalytic trials, and characterization of the Ga9Rh2 phase and the hitherto not-studied Ga3Rh phase. We used XRD and TEM for structural characterization, and with XPS, EDX we accessed the chemical composition and electronic structure of the intermetallic compounds. In combination with catalytic tests of these phases in the challenging propane dehydrogenation and by DFT calculations, we obtain a comprehensive picture of these novel catalyst materials. Their specific crystallographic structure leads to isolated Rhodium sites, which is proposed to be the decisive factor for the catalytic properties of the systems.

| S-EPMC10023779 | biostudies-literature

Subsurface catalysis-mediated selectivity of dehydrogenation reaction.

Project description:Progress in heterogeneous catalysis is often hampered by the difficulties of constructing active architectures and understanding reaction mechanisms at the molecular level due to the structural complexity of practical catalysts, in particular for multicomponent catalysts. Although surface science experiments and theoretical simulations help understand the detailed reaction mechanisms over model systems, the direct study of the nature of nanoparticle catalysts remains a grand challenge. This paper describes a facile construction of well-defined Pt-skin catalysts modified by different 3d transition metal (3dTM) atoms in subsurface regions. However, on the catalyst containing both surface and subsurface 3dTMs, the selectivity of propane dehydrogenation decreases in the sequences of Pt ~ PtFe > PtCo > PtNi due to the easier C-C cracking on exposed Co and Ni sites. After the exposed 3dTMs were removed completely, the C3H6 selectivity was found to increase markedly in the row Pt < PtNi@Pt < PtCo@Pt < PtFe@Pt, which is in line with the calculated trend of d-band center shifting. The established relationship between reactivity and d-band center shifting illustrates the role of subsurface catalysis in dehydrogenation reaction.

| S-EPMC6086612 | biostudies-literature

Ligand Postsynthetic Functionalization with Fluorinated Boranes and Implications in Hydrogenation Catalysis

Project description: Not available

| S-EPMC10852356 | biostudies-literature

Lithium diisopropylamide-mediated ortholithiations: lithium chloride catalysis.

Project description:Ortholithiations of a range of arenes mediated by lithium diisopropylamide (LDA) in THF at -78 degrees C reveal substantial accelerations by as little as 0.5 mol % of LiCl (relative to LDA). Substrate dependencies suggest a specific range of reactivity within which the LiCl catalysis is optimal. Standard protocols with unpurified commercial samples of n-butyllithium to prepare LDA or commercially available LDA show marked batch-dependent rates--up to 100-fold--that could prove significant to the unwary practitioner. Other lithium salts elicit more modest accelerations. The mechanism is not discussed.

| S-EPMC2765536 | biostudies-literature

Rhenium(VII) catalysis of Prins cyclization reactions.

Project description:The rhenium(VII) complex O3ReOSiPh3 is a particularly effective catalyst for Prins cyclizations using aromatic and alpha,beta-unsaturated aldehydes. The reaction conditions are mild, and the highly substituted 4-hydroxytetrahydropyran products are formed stereoselectively. Rhenium(VII) complexes appear to spontaneously form esters with alcohols and to directly activate electron-rich alcohols for solvolysis. Re2O7 and perrhenic acid are equally effective in catalyzing these cyclizations.

| S-EPMC2665917 | biostudies-literature

Enantioselective polyene cyclization via organo-SOMO catalysis.

Project description:The first organocatalytic enantioselective radical polycyclization has been accomplished using singly occupied molecular orbital (SOMO) catalysis. The presented strategy relies on a selective single-electron oxidation of chiral enamines formed by condensation of polyenals with an imidazolidinone catalyst employing a suitable copper(II) oxidant. The reaction proceeds under mildly acidic conditions at room temperature and shows compatibility with an array of electron-poor as well as electron-rich functional groups. Upon termination by radical arylation followed by subsequent oxidation and rearomatization, a range of polycyclic aldehydes were accessed (12 examples, 54-77% yield, 85-93% ee). The enantioselective formation of up to six new carbocycles in a single catalyst-controlled cascade is described. Evidence for a radical-based cascade mechanism is indicated by a series of experimental results.

| S-EPMC2880463 | biostudies-literature

Acceptorless dehydrogenation of small molecules through cooperative base metal catalysis.

Project description:The dehydrogenation of unactivated alkanes is an important transformation both in industrial and biological systems. Recent efforts towards this reaction have revolved around high temperature, organometallic C-H activation by noble metal catalysts that produce alkenes and hydrogen gas as the sole products. Conversely, natural desaturase systems proceed through stepwise hydrogen atom transfer at physiological temperature; however, these transformations require a terminal oxidant. Here we show combining tetra-n-butylammonium decatungstate (TBADT) and cobaloxime pyridine chloride (COPC) can catalytically dehydrogenate unactivated alkanes and alcohols under near-UV irradiation at room temperature with hydrogen as the sole by-product. This noble metal-free process follows a nature-inspired pathway of high- and low-energy hydrogen atom abstractions. The hydrogen evolution ability of cobaloximes is leveraged to render the system catalytic, with cooperative turnover numbers up to 48 and yields up to 83%. Our results demonstrate how cooperative base metal catalysis can achieve transformations previously restricted to precious metal catalysts.

| S-EPMC4682047 | biostudies-literature

Xanthene-4,5-diamine derivatives: a study of anion-binding catalysis.

Project description:This study describes the synthesis of a class of anion-binding catalysts based on a xanthene scaffold. Both unsymmetrical catalysts and C2-symmetrical catalysts were generated, and were examined in the cyclization of 3- and 2-substituted furans onto N-acyliminium ions. Good conversion for each reaction was observed with a variety of anion-binding catalysts (42-76%).

| S-EPMC4551103 | biostudies-literature

Allyl-Nickel Catalysis Enables Carbonyl Dehydrogenation and Oxidative Cycloalkenylation of Ketones.

Project description:We herein disclose the first report of a first-row transition metal-catalyzed α,β-dehydrogenation of carbonyl compounds using allyl-nickel catalysis. This development overcomes several limitations of previously reported allyl-palladium-catalyzed oxidation, and is further leveraged for the development of an oxidative cycloalkenylation reaction that provides access to bicycloalkenones with fused, bridged, and spirocyclic ring systems using unactivated ketone and alkene precursors.

| S-EPMC7495923 | biostudies-literature

Asymmetric synthesis of diamine derivatives via sequential palladium and rhodium catalysis.

Project description:The use of a bifunctional nitrogen nucleophile and an allyl carbonate starting material in successive enantioselective palladium- and diastereoselective rhodium-catalyzed reactions enables the rapid assembly of unique amino aziridine products. Further elaboration of these materials affords complex, stereodefined polyamine architectures, thus demonstrating the power of these combined methods for simplifying asymmetric C-N bond construction.

| S-EPMC3235049 | 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