Ullmann Cross-coupling Research Articles

Nitrogen-Rich Triptycene-Based Porous Polymer for Gas Storage and Iodine Enrichment.

A new kind of nitrogen-rich triptycene-based porous polymer (NTP) with high surface area of up to 1067 m2 g-1 was synthesized by a modified Yamamoto-type Ullmann cross-coupling reaction. Having structure features of expanded conjugated area and nitrogen atoms doping in polymer networks, the NTP displays extraordinary gas storage ability and excellent iodine adsorption capability.

Novel functionalized 1,5-diaza-3,7-diphosphacyclooctanes

GRAPHICAL ABSTRACT

Palladium-Catalyzed Ullmann Cross-Coupling/Tandem Reductive Cyclization Route to Key Members of the Uleine Alkaloid Family.

The trisubstituted cyclohexenone 12, generated through a palladium-catalyzed Ullmann cross-coupling reaction between o-iodonitrobenzene and a 4,5-trans-disubstituted 2-iodo-2-cyclohexen-1-one, engaged in a tandem reductive cyclization process upon exposure to hydrogen gas in the presence of Raney cobalt. As a result, the 1,5-methanoazocino[4,3-b]indole 13 was obtained and this could be readily elaborated to the racemic modifications of the alkaloids uleine, dasycarpidone, noruleine, and nordasycarpidone (1-4, respectively).

Ligand assisted copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines

Three types of ligands have been developed for copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines in aqueous solution. Ligands with large steric hindrance and strong electron-donating capacity were beneficial to the reaction. UV–Vis and CV analyses demonstrated that these ligands had strong coordination with copper(I), implying the effect of ligand coordination ability on the stability and catalytic activity of catalytic system.

Synthesis of marmycin A and investigation into its cellular activity.

Anthracyclines such as doxorubicin are used extensively in the treatment of cancers. Anthraquinone-related angucyclines also exhibit antiproliferative properties and have been proposed to operate via similar mechanisms, including direct genome targeting. Here, we report the chemical synthesis of marmycin A and the study of its cellular activity. The aromatic core was constructed by means of a one-pot multistep reaction comprising a regioselective Diels-Alder cycloaddition, and the complex sugar backbone was introduced through a copper-catalysed Ullmann cross-coupling, followed by a challenging Friedel-Crafts cyclization. Remarkably, fluorescence microscopy revealed that marmycin A does not target the nucleus but instead accumulates in lysosomes, thereby promoting cell death independently of genome targeting. Furthermore, a synthetic dimer of marmycin A and the lysosome-targeting agent artesunate exhibited a synergistic activity against the invasive MDA-MB-231 cancer cell line. These findings shed light on the elusive pathways through which anthraquinone derivatives act in cells, pointing towards unanticipated biological and therapeutic applications.

ChemInform Abstract: Efficient C—S Cross‐Coupling of Thiols with Aryl Iodides Catalyzed by Cu(OAc)2·H2O and 2,2′‐Biimidazole.

AbstractA highly efficient, mild, simple, and economically attractive copper catalyzed C‐S Ullmann cross coupling of both aryl and alkyl thiols with aryl halides is developed.

An efficient regioselective copper catalyzed multi-component synthesis of 1,3-disubstituted pyrazoles

An efficient synthesis of unsymmetrically substituted 1,3-pyrazole derivatives has been developed via three-component coupling reaction involving 3-(dimethylamino)-1-phenylprop-2-en-1-one, hydrazine, and aryl halides in one pot process exhibiting high regioselectivity. The pyrazole synthesis proceeds via a sequential series of reactions such as Michael addition, heterocyclization, dehydration, and Ullmann cross-coupling.

Synthesis and Gas Adsorption Properties of Tetra‐Armed Microporous Organic Polymer Networks Based on Triphenylamine

Two novel tetra-armed microporous organic polymers have been designed and synthesized via a nickel-catalyzed Yamamoto-type Ullmann cross-coupling reaction or Suzuki cross-coupling polycondensation. These polymers are stable in various solvents, including concentrated hydrochloric acid, and are thermally stable. The homocoupled polymer YPTPA shows much higher Brunauer-Emmet-Teller-specific surface area up to 1557 m(2) g(-1) than the copolymer SPTPA (544 m(2) g(-1)), and a high CO2 uptake ability of 3.03 mmol g(-1) (1.13 bar/273 K) with a CO2 /N2 sorption selectivity of 17.3:1. Both polymers show high isosteric heats of CO2 adsorption (22.7-26.5 kJ mol(-1)) because the incorporation of nitrogen atoms into the skeleton of microporous organic polymers enhances the interaction between the pore wall and the CO2 molecules. The values are higher than those of the porous aromatic frameworks, which contain neither additional polar functional groups nor nitrogen atoms, and are rather close to those of previously reported microporous organic polymers containing the nitrogen atoms on the pore wall. These data show that these materials would be potential candidates for applications in post-combustion CO2 capture and sequestration technology.

Synthesis of copolymerized porous organic frameworks with high gas storage capabilities at both high and low pressures

A series of copolymerized porous organic frameworks (C-POFs) were synthesized with monomers of tetrakis(4-bromophenyl)methane and tris(4-bromophenyl)amine in different ratios by a Yamamoto-type Ullmann cross-coupling reaction. These C-POFs exhibit high physicochemical stability, large surface areas and excellent H2, CH4 and CO2 adsorption properties both at low and high pressures.

Copper-catalyzed Ullmann-type synthesis of diaryl ethers assisted by salicylaldimine ligands

Abstract A series of salicylaldimine ligands were designed to promote the copper-catalyzed Ullmann cross-coupling reaction. After a screening process, 2-((2-isopropylphenylimino)methyl)phenol was found to serve as a good supporting ligand for this reaction. Employing this Schiff-base ligand as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. Various diaryl ethers were obtained with excellent yields in dioxane in the presence of K3PO4 and a catalytic amount of copper(I) salt.

Targeted synthesis of electroactive porous organic frameworks containing triphenyl phosphine moieties

A novel electroactive porous aromatic framework (JUC-Z4-Cl) was designed and synthesized via Yamamoto-type Ullmann cross-coupling reaction with the monomer tris(4-chlorophenyl)phosphine. By simple redox chemical reactions, stable, reductive, porous polytri(p-phenyl)phosphine (JUC-Z4) and polytri(p-phenyl)phosphine oxide (JUC-Z5) could be obtained as off-white powders. The structures of JUC-Z4 and JUC-Z5 were confirmed using magic-angle spinning nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, etc. The microporous architectures exhibit high stability (471°C for JUC-Z4 and 484°C for JUC-Z5) and large surface area (793 and 648 m² g⁻¹ for JUC-Z4 and JUC-Z5, respectively). JUC-Z4 also exhibits efficient recognition ability of greenhouse gases from dry air.

ChemInform Abstract: A Pd[0]‐Catalyzed Ullmann Cross‐Coupling/Reductive Cyclization Approach to C‐3 Mono‐Alkylated Oxindoles and Related Compounds.

The Pd[0]-catalyzed Ullmann cross-coupling of o-nitrohaloarenes 1a–e with the brominated heterocycles 2a–f delivers the expected products 3a–j in good to excellent yields. The reductive cyclization of such products, as well as N-acyl derivatives 3k, l, and m, has been investigated and provided the C-3 mono-substituted oxindoles 5a–d, f, g, k, and m, the direct reduction products 4i and j or indole 5l.

Tubulin-binding dibenz[c,e]oxepines as colchinol analogues for targeting tumour vasculature

Various methoxy- and hydroxy-substituted dibenz[c,e]oxepines were prepared via the copper(I)-induced coupling of ether-tethered arylstannanes or the dehydrative cyclisation of 1,1'-biphenyl-2,2'-dimethanols, assembled using the Ullmann cross-coupling of ortho-bromoaryl carbonyl compounds. The dibenzoxepines were screened for their ability to inhibit tubulin polymerisation and the in vitro growth of K562 human chronic myelogenous leukemia cells. The most active was 5,7-dihydro-3,9,10,11-tetramethoxydibenz[c,e]oxepin-4-ol, whose tubulin inhibitory and cytotoxicity (IC(50)) values were 1 μM and 40 nM, respectively.

A Pd[0]-catalyzed Ullmann cross-coupling/reductive cyclization approach to C-3 mono-alkylated oxindoles and related compounds

The Pd[0]-catalyzed Ullmann cross-coupling of o-nitrohaloarenes 1a– e with the brominated heterocycles 2a– f delivers the expected products 3a– j in good to excellent yields. The reductive cyclization of such products, as well as N-acyl derivatives 3k, l, and m, has been investigated and provided the C-3 mono-substituted oxindoles 5a– d, f, g, k, and m, the direct reduction products 4i and j or indole 5l.

Unsymmetrical Biaryls by Pd-Catalyzed Cross-Coupling of Iodoarenes

Based on the reactivity difference between aryl iodides and the stoichiometric ratio used, the authors have developed an unsymmetrical version of the Ullmann cross-coupling with a convenient catalytic system of Pd(OAc)2/K2CO3/MeCOEt to afford unsymmetrical biaryl products in good yields.

The synthesis of compounds related to the indole–indoline core of the vinca alkaloids (+)-vinblastine and (+)-vincristine

A series of α′-aryl-α′-carbomethoxycycloalk-2-en-1-ones, 16, has been prepared using the Pinhey arylation methodology for introducing the aromatic residue. Subjection of these compounds to Johnson iodination and Pd[0]-catalyzed Ullmann cross-coupling of the resulting α-iodocycloalkenones 11 with 2-iodonitrobenzene ( 5, X = I) then affords α,α′-diaryl-α′-carbomethoxycycloalk-2-en-1-ones of the general form 10. Reductive cyclization of this last type of compound gives the corresponding indoles 9a– f ( n = 1–3), some of which resemble the indole–indoline cores of the clinically important alkaloids (+)-vinblastine ( 1) and (+)-vincristine ( 2).

Synthesis of Santiagonamine

The first total synthesis of santiagonamine (1) is achieved in 12 steps from isovanillin. A palladium-catalyzed Ullmann cross-coupling reaction and a photocyclization are the key steps in the synthesis.

New protocols for the synthesis of 3,4-annulated and 4-substituted quinolines from β-bromo-α,β-unsaturated aldehydes and 1-bromo-2-nitrobenzene or 2-bromoacetanilide

The palladium[0]-mediated Ullmann cross-coupling of readily available β-bromo-α,β-unsaturated aldehydes of the general form 2 with 1-bromo-2-nitrobenzene ( 3, X = Br) delivers products, 4, that undergo reductive cyclization to novel quinolines ( 5) upon exposure to indium in aqueous ammonium chloride or to Raney-nickel in the presence of dihydrogen. Analogous cross-coupling of 2-bromoacetanilide ( 6) with 2 affords products of type 7 that undergo in situ and K 2CO 3-mediated cyclization to give the same types of quinolines ( 5).

Synthesis of substituted benzene derivatives by homo- and hetero-coupling of 2-bromobenzaldehyde and bromovinylaldehydes followed by McMurry coupling

A convenient synthetic approach to substituted benzene derivatives by modified Ullmann cross-coupling of 2-bromobenzaldehyde and bromovinylaldehydes followed by intramolecular McMurry coupling has been developed.

Application of the Palladium(0)-Catalyzed Ullmann Cross-Coupling Reaction in a Total Synthesis of (±)-Aspidospermidine and thus Representing an Approach to the Lower Hemisphere of the Binary Indole - Indoline Alkaloid Vinblastine

As part of ongoing studies directed towards the construction of the anti-cancer agent vinblastine (1), the related but structurally less complex natural product aspidospermidine (3) has been synthesized. Two approaches to target 3 were pursued. In the first, which was unsuccessful, the amine-tethered enone 6 was prepared but this failed to engage in the pivotal intramolecular conjugate addition reaction to give the bicyclic system 5. In contrast, the related compound 46, incorporating tethered enone and azide moieties, engaged in an intramolecular 1,3-dipolar cycloaddition reaction to give, presumably via an intermediate triazoline, the isolable and ring-fused aziridine 47. This was then converted, over two steps, into the previously reported tetrahydrocarbazole 4. Application of established protocols to this last compound allowed for the installation of the E-ring of the title alkaloid 3 and completion of the total synthesis.