Hydrocarbons

Griesbaum, Karl; Behr, Arno; Biedenkapp, Dieter; Voges, Heinz-Werner; Garbe, Dorothea; Paetz, Christian; Collin, Gerd; Mayer, Dieter; Höke, Hartmut; Schmidt, Roland

doi:10.1002/14356007.a13_227.pub2

Cited by 4 publications

(2 citation statements)

References 92 publications

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“…Conjugated dienes are synthetically versatile feedstocks that are readily accessible by a variety of synthetic methods or produced industrially on multiton scales . Carboamination of dienes is an emergent strategy that can enable simultaneous construction of C–C and C–N bonds of a nitrogenous allylic system in a multicomponent fashion without prior assembly of an allylic fragment. − However, control of the regio- and stereoselectivity of diene carboamination has remained a challenge and has primarily been limited to 1,2-carboamination, while 1,4-carboamination has remained underdeveloped and has relied on palladium and other precious metals, with no examples of base metal catalytic systems.…”

Section: Introductionmentioning

confidence: 99%

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

Zhuang,

Haug,

Wang

et al. 2024

J. Am. Chem. Soc.

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Tricomponent cobalt(salen)-catalyzed carbofunctionalization of unsaturated substrates by radical−polar crossover has the potential to streamline access to broad classes of heteroatom-functionalized synthetic targets, yet the reaction platform has remained elusive, despite the well-developed analogous hydrofunctionalizations mediated by high-valent alkylcobalt intermediates. We report herein the development of a cobalt(salen) catalytic system that enables carbofunctionalization. The reaction entails a tricomponent decarboxylative 1,4-carboamination of dienes and provides a direct route to aromatic allylic amines by obviating preformed allylation reagents and protection of oxidation-sensitive aromatic amines. The catalytic system merges acridine photocatalysis with cobalt(salen)-catalyzed regioselective 1,4-carbofunctionalization that facilitates the crossover of the radical and polar phases of the tricomponent coupling process, revealing critical roles of the reactants, as well as ligand effects and the nature of the formal high-valent alkylcobalt species on the chemo-and regioselectivity.

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Section: Introductionmentioning

confidence: 99%

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

Zhuang,

Haug,

Wang

et al. 2024

J. Am. Chem. Soc.

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“…The catalytic transformation of feedstock olefins and dienes to value-added chemicals is of long-standing interest for the synthesis of small molecules and polymers. 1 Molecular catalysts offer the distinct advantage of rational ligand modification to alter and optimize catalyst performance. 2 − 4 The independent discoveries by Brookhart and Gibson that activation of high-spin pyridine(diimine) (PDI) iron(II) and cobalt(II) complexes with methylaluminoxane (MAO) generates highly active catalysts for the polymerization of ethylene and selected α-olefins, demonstrated the rich C–C bond-forming chemistry available from open-shell, first-row transition-metal catalysts.…”

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confidence: 99%

C_S-Symmetric Pyridine(diimine) Iron Methyl Complexes for Catalytic [2+2] Cycloaddition and Hydrovinylation: Metallacycle Geometry Determines Selectivity

Duchemin

Kim

Chirik

2023

JACS Au

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A series of C S -symmetric (aryl,alkyl)-substituted pyridine(dimine) iron methyl ( Cy A R PDI)FeCH 3 complexes have been prepared, characterized, and evaluated as precatalysts for the [2+2]-cycloaddition of butadiene and ethylene. Mixtures of vinylcyclobutane and (Z)-hexa-1,4-diene were observed in each case. By comparison, C 2v -symmetric, arylated (PDI) iron catalysts are exclusively selective for reversible [2+2]-cycloaddition to yield vinylcyclobutane. The alteration in the chemoselectivity of the catalytic reaction was investigated through a combination of precatalyst stability studies, identification of catalytic resting state(s), and 2 H and 13 C isotopic labeling experiments. While replacement of an aryl-imine substituent with an N-alkyl group decreases the stability of the formally iron(0) dinitrogen and butadiene complexes, two diamagnetic metallacycles were identified as catalyst resting states. Deuterium labeling and NOESY/EXSY NMR experiments support 1,4-hexadiene arising from catalytic hydrovinylation involving reversible oxidative cyclization leading to accessible cis-metallacycle. Cyclobutane formation proceeds by irreversible C(sp 3 )−C(sp 3 ) bond-forming reductive elimination from a trans-metallacycle. These studies provide key mechanistic understanding into the high selectivity of bis(arylated) pyridine(diimine) iron catalysts for [2+2]-cycloaddition, unique, thus far, to this class of iron catalysts.

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Characterization of paraffin oils and petrolatum using LDI‐TOF MS and principle component analysis

Prunsa

Rapp

Hintze

et al. 2003

Euro J Lipid Sci & Tech

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Laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) followed by evaluation of the mass spectra with principal component analysis (PCA) was used for the in-depth characterization of paraffin oils (mineral oils) and petrolatum (paraffin jelly) samples. These raw materials are liquid and semisolid mixtures of hydrocarbons obtained from petroleum. Mass spectrometric analysis was done using a solvent-free sample preparation with silver trifluoroacetate. The analysis was carried out on a commercially available matrix-assisted laser desorption/ionization time-of-flight mass spectrometer.Mass spectra were evaluated using parameters calculated from the areas of different alkane and cycloalkane species and by PCA. The ratios between specific peak areas were chosen as PCA-input data instead of the less reproducible absolute peak areas.The principal components enable comparison of a large number of samples and can also be used for visualization of data. In this work, it is clearly demonstrated that combining LDI-TOF MS and PCA provides a fast and efficient tool for the characterization of paraffin oils and petrolatum. Petrolatum and four different kinds of paraffin oil were analyzed and the results compared with other analytical methods.

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Hydrocarbons

Cited by 4 publications

References 92 publications

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

C_S-Symmetric Pyridine(diimine) Iron Methyl Complexes for Catalytic [2+2] Cycloaddition and Hydrovinylation: Metallacycle Geometry Determines Selectivity

Characterization of paraffin oils and petrolatum using LDI‐TOF MS and principle component analysis

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Hydrocarbons

Cited by 4 publications

References 92 publications

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

Cobalt-Catalyzed Carbon–Heteroatom Transfer Enables Regioselective Tricomponent 1,4-Carboamination

CS-Symmetric Pyridine(diimine) Iron Methyl Complexes for Catalytic [2+2] Cycloaddition and Hydrovinylation: Metallacycle Geometry Determines Selectivity

Characterization of paraffin oils and petrolatum using LDI‐TOF MS and principle component analysis

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Product

Resources

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C_S-Symmetric Pyridine(diimine) Iron Methyl Complexes for Catalytic [2+2] Cycloaddition and Hydrovinylation: Metallacycle Geometry Determines Selectivity