Palladium-catalyzed Carbonylative Reaction Research Articles

Palladium-Catalyzed Enantioselective Intramolecular Heck Carbonylation Reactions: Asymmetric Synthesis of 2-Oxindole Ynones and Carboxylic Acids.

Herein, we report a Pd-catalyzed enantioselective domino Heck carbonylation reaction of o-iodoacrylanilides with terminal alkynes and water as the nucleophiles, affording a diversity of β-carbonylated 2-oxindole derivatives bearing a 3,3-disubstituted all-carbon quaternary stereocenter, in high yields (55-99 %) with good to excellent enantioselectivities (up to 99 % ee). The synthetic utilities of the protocol were demonstrated in the gram-scale synthesis of 2-oxindole-derived ynone 3 ea and carboxylic acid 4 a, as well as the facile synthesis of chiral 2-oxindoles with a pyrazole or isoxazole moiety.

Nickel-Catalyzed Reductive Asymmetric Aryl-Acylation and Aryl-Carbamoylation of Unactivated Alkenes

Nickel-Catalyzed Reductive Asymmetric Aryl-Acylation and Aryl-Carbamoylation of Unactivated Alkenes

Palladium-catalyzed carbonylative synthesis of quinazolines: Silane act as better nucleophile than amidine

Abstract A palladium-catalyzed reductive carbonylation reaction has been developed for the synthesis of quinazolines. With N-(2-iodophenyl)benzimidamide as starting materials, a series of quinazolines were obtained through the aromatic aldehyde intermediates in moderate to good yields with good functional group compatibilities. In this system, silane act as better nucleophile than amidine.

Synthesis of novel aromatic polyamides containing both sulfone linkages and cardo groups by a recyclable palladium-catalyzed carbonylation and condensation polymerization

A series of novel aromatic polyamides containing both sulfone linkages and cardo groups were synthesized via a heterogeneous palladium-catalyzed carbonylation and condensation reaction of aromatic diiodides bearing ether sulfone linkages, carbon monoxide, and aromatic diamines with cardo groups. Polycondensation reaction proceeded smoothly under 1 atm of CO at 120 °C in N,N-dimethylacetamide (DMAc) by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored palladium complex [2P-Fe3O4@SiO2-PdCl2] as a recyclable catalyst with 1,8-diazabicycle[5,4,0]-7-undecene (DBU) as a base, furnishing cardo poly(ether sulfone amide)s with inherent viscosities between 0.70 and 0.77 dL/g. The resulting polyamides could be readily dissolved in polar aprotic organic solvents and even dissolved in less polar pyridine and tetrahydrofuran at room temperature and could be easily converted into flexible, transparent, and tough films via casting from their solutions in DMAc. These polymers exhibited excellent thermal stability with the glass transition temperatures between 241 and 283 °C and the temperatures at 5% weight loss ranging from 438 to 475 °C in an atmosphere of nitrogen. The polyamide films displayed good mechanical behavior with tensile strengths of 78.8–84.4 MPa, tensile moduli of 2.08–2.57 GPa, and elongations at breakage of 10.2–12.5%, and optically high transparency with cut-off wavelengths in the range of 338–368 nm.

Palladium-Catalyzed Cascade Carbonylative Synthesis of 1,2,4-Triazol-3-ones from Hydrazonoyl Chlorides and NaN3.

A palladium-catalyzed three-component carbonylative reaction for the synthesis of 3H-1,2,4-triazol-3-ones from hydrazonoyl chlorides and NaN3 has been achieved. The reaction presumably proceeds through a cascade carbonylation, acyl azide formation, Curtius rearrangement, and intramolecular nucleophilic addition sequence. A wide variety of structurally diverse 3H-1,2,4-triazol-3-ones were constructed in moderate to excellent yields. Benzene-1,3,5-triyl triformate (TFBen) was applied as a solid and convenient CO surrogate.

Solar photothermal catalytic effect promotes carbonylation reaction based on palladium doped g-C3N4 catalyst

Palladium catalyzed carbonylation reaction is used as an effective method in the industrial to prepare carbonyl-containing compounds. Besides, the complex ligands are needed to improve the yields and selectivity of reactions, which will increase the cost for production. Thus, it is very meaningful to build a simple and efficient catalytic system. Here, the graphitic carbon nitride (g-C3N4) nanosheets (ECN) doped with palladium metal (Pd/ECN) were prepared by microwave-assisted deposition method. The results indicated that the yield of methyl benzoate was 77 % based on Pd/ECN under the light irradiation with a wavelength of ≥ 400 nm, which was higher than that of the homogeneous catalysts and heterogeneous catalysts commonly used in commercialization such as palladium on activated charcoal (Pd/C) and palladium chloride (PdCl2).

CO Surrogates: A Green Alternative in Palladium-Catalyzed CO Gas Free Carbonylation Reactions

Carbonylation reactions with carbon monoxide (CO) provide efficient and attractive routes for the synthesis of bulk and fine chemicals. However, the practice of using a large excess of an inflammable, lethal and greenhouse CO gas is always a concern in this chemistry. The development of CO surrogates has gained substantial interest and become a green alternative to gaseous CO. Many of the recent studies have focused on the development of other benign and safe reagents to work as a CO source in carbonylation reactions, and the assortment of feasible CO surrogates for specific reaction can be accomplished by the literature data. This review describes the recent developments in palladium-catalyzed carbonyl insertions without the direct use of gaseous CO.

Hybrides of Alkaloid Lappaconitine with Pyrimidine Motif on the Anthranilic Acid Moiety: Design, Synthesis, and Investigation of Antinociceptive Potency.

Convenient and efficient routes to construct hybrid molecules containing diterpene alkaloid lappaconitine and pyrimidine fragments are reported. One route takes place via first converting of lappaconitine to 1-ethynyl-lappaconitine, followed by the Sonogashira cross-coupling-cyclocondensation sequences. The other involves the palladium-catalyzed carbonylative Sonogashira reaction of 5′-iodolappaconitine with aryl acetylene and Mo (CO)6 as the CO source in acetonitrile and subsequent cyclocondensation reaction of the generated alkynone with amidines. The reaction proceeded cleanly in the presence of the PdCl2-(1-Ad)2PBn∙HBr catalytic system. The protocol provides mild reaction conditions, high yields, and high atom and step-economy. Pharmacological screening of lappaconitine-pyrimidine hybrids for antinociceptive activity in vivo revealed that these compounds possessed high activity in experimental pain models, which was dependent on the nature of the substituent in the 2 and 6 positions of the pyrimidine nucleus. Docking studies were undertaken to gain insight into the possible binding mode of these compounds with the voltage-gated sodium channel 1.7. The moderate toxicity of the leading compound 12 (50% lethal dose (LD50) value was more than 600 mg/kg in vivo) and cytotoxicity to cancer cell lines in vitro encouraged the further design of therapeutically relevant analogues based on this novel type of lappaconitine–pyrimidine hybrids.

Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium-catalyzed carbonylation and condensation reaction

New aromatic polyamides containing cardo groups and triphenylphosphine oxide structures were synthesized by a heterogeneous palladium-catalyzed carbonylation and condensation of bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), aromatic diamines bearing cardo groups, and carbon monoxide. Polycondensations were carried out in N,N-dimethylacetamide under 1 atm of CO at 120 °C in the presence of a magnetically recyclable heterogeneous palladium catalyst and 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU) and afforded novel aromatic polyamides with inherent viscosities between 0.72 and 0.76 dL/g. All the polyamides were quite soluble in dipolar aprotic solvents and pyridine and could be converted into transparent, flexible, and tough polyamide films by casting from DMAc solutions. These polymers exhibited high thermal and thermooxidative stability with the glass transition temperatures of 237 °C–256 °C, the temperatures at 5% weight loss of 448 °C–465 °C in air. All the phosphorus-containing polyamides self-extinguished as soon as the flame was removed, and the limited oxygen indices (LOIs) of these polymers were in the range of 39%–44%. The polymer films also showed good mechanical properties and high optical transparency.

Renewable Solvents for Palladium-Catalyzed Carbonylation Reactions

Solvents constitute the largest component for many chemical processes and substitution of nonrenewable solvents is a longstanding goal for green chemistry. Here, we show that Pd-catalyzed carbonyla...

Palladium-Catalyzed Four-Component Carbonylative Cyclization Reaction of Trifluoroacetimidoyl Chlorides, Propargyl Amines, and Diaryliodonium Salts: Access to Trifluoromethyl-Containing Trisubstituted Imidazoles.

A palladium-catalyzed four-component carbonylative cyclization reaction for the expeditious construction of trifluoromethyl-containing trisubstituted imidazoles has been achieved. With readily accessible trifluoroacetimidoyl chlorides, propargyl amines, and diaryliodonium salts as the starting materials, the carbonylative transformation proceeds smoothly under mild conditions to enable the formation of multifunctionalized imidazole molecules in a one-pot, one-step manner. Diaryliodonium salts serve as both oxidants and aryl sources in the reaction.

Palladium-catalyzed oxidative dehydrogenative carbonylation reactions using carbon monoxide and mechanistic overviews.

Carbon monoxide, which is an abundant and inexpensive carbonyl source, has been widely applied to synthesize carbonyl-containing compounds, for example ketones, esters, and amides. These types of compounds are ubiquitous in natural products, pharmaceuticals, as well as in functional materials. This review focuses on the palladium-catalyzed dehydrogenative C-H/X-H (X = C, N, O) carbonylation transformations under oxidative conditions. The related C-H bonds here include C(sp)-H, C(sp2)-H, and C(sp3)-H bonds. From a step- and atom-economy perspective, transition metal-catalyzed oxidative dehydrogenative C-H/X-H carbonylation reactions with CO constitute one of the most efficient strategies for the construction of versatile carbonyl groups, without the requirement of pre-functionalized substrates.

Palladium-catalyzed three-component carbonylative synthesis of 2-(trifluoromethyl)quinazolin-4(3H)-ones from trifluoroacetimidoyl chlorides and amines

An efficient and practical approach for the synthesis of 2-(trifluoromethyl)quinazolin-4(3H)-ones through palladium-catalyzed three-component carbonylative reaction has been developed.

Two-Photon Absorption and Cell Imaging of Fluorene-Functionalized Epicocconone Analogues.

Epicocconone 1 is a natural chromophore isolated from the fungus Epicoccum nigrum that has shown applications in proteomics and fluorescent microscopy thanks to its unique pro-fluorescence properties. The modification of the skeleton of the natural product by replacing the triene side chain by a fluorenyl scaffold can noticeably increase the fluorophore's absorption coefficient. The synthesis of the analogues of the natural product has been made possible by the use of a palladium-catalyzed carbonylation reaction, allowing the construction of the β-keto-dioxinone key intermediate. Two-photon absorption cross-section measurements of the fluorenyl epicocconone analogues show a structure dependency with values ranging from 60 to 280 GM and live cell imaging show intense staining of intracellular vesicle-like structures around the nucleus.

Palladium-Catalyzed Tunable Carbonylative Synthesis of Enones and Benzofulvenes.

A palladium-catalyzed four-component carbonylative coupling reaction involving aryl halides, internal alkynes, arylboronic acids, and CO has been developed for the first time. All-carbon substituted α-unsaturated ketones and benzofulvenes can be selectively obtained in a highly regio- and stereocontrolled manner. Using Cu(TFA)2 as the additive, a series of tetrasubstituted α-unsaturated ketones were prepared in moderate to high yields. Using more acidic Lewis acid Cu(OTf)2 as the additive, multisubstituted benzofluvenes were synthesized in moderate yields. This efficient methodology involved the formation of three new C-C bonds, and provided a divergent method for the quick construction of multisubstituted α-unsaturated ketones and benzofulvenes from easily available starting materials.

Carbonylated Indoles from PdII-Catalyzed Intermolecular Reactions of Indolyl Cores

This review summarizes palladium-catalyzed carbonylation, transmetalation, and cross-coupling reactions that lead to carbonylated indoles from indoles and indolyl compounds. Special attention is drawn to procedures involving the C(sp2)–H substitution of free (NH)-indoles or (N-substituted)-indoles. Proposed mechanisms are described with, in some cases, personal comments.1 Introduction2 Carbonylative Reactions2.1 Indolyl Halides as Starting Substrates2.2 Indolyl Iodides as Intermediates2.3 Indolylborates as Intermediates2.4 C(sp2)–H Reactions2.4.1 Carboxylation2.4.2 Carbonylative Alkoxylation2.4.3 Carbonylative Arylation2.4.4 Carbonylative Alkenylation2.4.5 Carbonylative Alkylation2.4.6 Double Carbonylation3 Cross-Coupling of Stannyl- or Mercurioindoles4 Cross-Coupling of Indoles4.1 Aldehydes4.2 Alcohols4.3 α-Diketones4.4 α-Oxo Esters4.5 α-Oxocarboxylic Acids4.6 Nitriles4.7 Isocyanides4.8 Isothiocyanates and Isocyanates4.9 α-Aminocarbonyl Compounds4.10 Vinyl Ethers or Vinyl Amides4.11 Toluene and Substituted Toluenes4.12 Bromodichloromethane5 Conclusion

“CO” as a Carbon Bridge to Build Complex C2-Branched Glycosides Using a Palladium-Catalyzed Carbonylative Suzuki–Miyaura Reaction from 2-Iodoglycals

Development of a palladium-catalyzed carbonylative Suzuki-Miyaura coupling reaction between 2-iodoglycal partners and diverse aryl- and alkenyl-boronic acids is presented, leading to original 2-ketoglycals. The newly formed carbonyl link could be exploited to access 2-aryl/alkenyl-methylene-α-glucopyranoside scaffolds via a three-step sequence including an indium-mediated Ferrier-type reaction.

Palladium catalyzed carbonylations of alkenyl halides with formic acid to get corresponding α,β-unsaturated carboxylic acids and esters

Palladium-catalysed carbonylation reactions have been developed in the presence of formic acid as carbon monoxide source. α,β-Unsaturated carboxylic acids and esters were synthesized by the transformation of alkenyl halides in moderate to good yields. The selection of the base proved to be crucial regarding the reaction outcome. A set of various substrates were proven under optimised reaction conditions. Compared to aliphatic alcohols, phenols showed excellent reactivity as O-nucleophiles.

A Convenient Palladium‐Catalyzed Carbonylative Synthesis of (E)‐3‐Benzylidenechroman‐4‐ones

A convenient palladium-catalyzed carbonylation reaction for the efficient synthesis of (E)-3-benzylidenechroman-4-ones has been developed. Using TFBen as a solid CO source, a range of substituted (E)-3-benzylidenechroman-4-ones were prepared in moderate to good yields with 2-iodophenols and allyl chlorides as the substrates. Additionally, substituted quinolin-4(1H)-ones can also be obtained with 2-iodoaniline as the starting material.

Palladium-catalyzed carbonylative Sonogashira cross-coupling for the synthesis of alkynones with formic acid as the CO source

A practical and efficient palladium-catalyzed carbonylative Sonogashira cross-coupling reaction for the synthesis of alkynones from aryl iodides, alkynes, and formic acid as the CO source has been described. Under the assistance of PPh3/I2, formic acid can be used as the CO source for synthesis of alkynones in moderate–good yields. Furthermore, it is also successfully applied for the modification of natural products, such as vindoline and tabersonin, to obtain the corresponding products.