Nickel‐Catalyzed C(sp2)−C(sp3) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl Grignard Reagents

2019

Aryl tosylates are an attractive class of electrophiles for cross‐coupling reactions due to ease of synthesis, low price, and the employment of C−O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni‐catalyzed C(sp2)−C(sp3) Kumada cross‐coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross‐coupling with challenging alkyl organometallics possessing β‐hydrogens that are prone to β‐hydride elimination and homo‐coupling. The reaction is catalyzed by an air‐ and moisture stable‐Ni(II) precatalyst. A broad range of electronically‐varied aryl tosylates, including bis‐tosylates, underwe…

Cobalt−NHC Catalyzed C(sp 2 )−C(sp 3 ) and C(sp 2 )−C(sp 2 ) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents

2020

Eisenkatalysierte Kreuzkupplungen in der Synthese von Pharmazeutika: Streben nach Nachhaltigkeit

2018

Iron-Catalyzed C(sp2)-C(sp3) Cross-Coupling of Alkyl Grignard Reagents with Polyaromatic Tosylates

2017

Iron‐Catalyzed Cross‐Couplings in the Synthesis of Pharmaceuticals: In Pursuit of Sustainability

2018

The scarcity of precious metals has led to the development of sustainable strategies for metal-catalyzed cross-coupling reactions. The establishment of new catalytic methods using iron is attractive owing to the low cost, abundance, ready availability, and very low toxicity of iron. In the last few years, sustainable methods for iron-catalyzed cross-couplings have entered the critical area of pharmaceutical research. Most notably, iron is one of the very few metals that have been successfully field-tested as highly effective base-metal catalysts in practical, kilogram-scale industrial cross-couplings. In this Minireview, we critically discuss the strategic benefits of using iron catalysts a…

Structures and energetic properties of 4-halobenzamides

2018

The amide bond represents one of the most fundamental functional groups in chemistry. The properties of amides are defined by amidic resonance (nN→π*C=O conjugation), which enforces planarity of the six atoms comprising the amide bond. Despite the importance of 4-halo-substituted benzamides in organic synthesis, molecular interactions and medicinal chemistry, the effect of 4-halo-substitution on the properties of the amide bond in N,N-disubstituted benzamides has not been studied. Herein, we report the crystal structures and energetic properties of a full series of 4-halobenzamides. The structures of four 4-halobenzamides (halo = iodo, bromo, chloro and fluoro) in the N-morpholinyl series h…

Titanium and Vanadium Catalysts with 2-Hydroxyphenyloxazoline and Oxazine Ligands for Ethylene-Norbornene (co)Polymerization

2019

A series of titanium and vanadium complexes with oxazoline 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol (L1), 2-(4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenol (L2), and oxazine 2-(5,6-dihydro-4H-1,3-oxazin-2-yl)phenol (L3) ligands were synthesized, and their structures were determined by NMR and MS methods as (L)2MtCl2. The vanadium complexes were found to be highly active in ethylene (7300 kgPE/(molV&middot

Naphthalene-2,6-diyl bis(4-methylbenzenesulfonate)

2018

The complete molecule of the title compound, C24H20O6S2, is generated by a crystallographic inversion centre at the middle of the naphthalene ring system. The dihedral angle between the naphthalene ring system and the pendant benzene ring is 10.23 (6)° and the C—S—O—C torsion angle is −172.05 (10)°. In the crystal, weak C—H...O interactions link the molecules into (10-1) sheets.

Iron-catalyzed C(sp2)-C(sp3) cross-coupling at low catalyst loading

2019

The iron-catalyzed C(sp2)–C(sp3) cross-coupling provides a highly economical route to exceedingly valuable alkylated arenes that are widespread in medicinal chemistry and materials science. Herein, we report an operationally-simple protocol for the selective C(sp2)–C(sp3) iron-catalyzed cross-coupling of aryl chlorides with Grignard reagents at low catalyst loading. A broad range of electronically-varied aryl and heteroaryl chlorides underwent the cross-coupling using challenging alkyl organometallics possessing β-hydrogens with high efficiency up to 2000 TON. A notable feature of the protocol is the use of environmentally-friendly cyclic urea ligands. A series of guidelines to predict cros…

Structural and Thermal Properties of Ethylene-Norbornene Copolymers Obtained Using Vanadium Homogeneous and SIL Catalysts

2020

The series of ethylene-norbornene (E-NB) copolymers was obtained using different vanadium homogeneous and supported ionic liquid (SIL) catalyst systems. The 13C and 1H NMR (carbon and proton nuclear magnetic resonance spectroscopy) together with differential scanning calorimetry (DSC) were applied to determine the composition of copolymers such as comonomer incorporation (CNB), monomer dispersity (MD), monomer reactivity ratio (re), sequence length of ethylene (le) and tetrad microblock distributions. The relation between the type of catalyst, reaction conditions and on the other hand, the copolymer microstructure, chain termination reaction analyzed by the type of unsaturation are discusse…

4-Chloronaphthalen-1-yl 4-methylbenzenesulfonate

2018

In the title compound, C17H13ClO3S, the naphthalene ring system and the benzene ring of the tosylate substituent are inclined to one another by 55.32 (5)°. The crystal structure features weak intermolecular C—H...O hydrogen bonds, one of which forms inversion dimers. Additional C—H...O hydrogen bonds and weak Cl...Cl halogen bonds stack the molecules along the b-axis direction.