Pd-catalyzed Carbonylation Research Articles

Amide bond formation via C(sp3)–H bond functionalization and CO insertion

An efficient method for the synthesis of amides via Pd-catalyzed oxidative carbonylation of C(sp(3))-H bonds with CO and amines is described. The route efficiently provides substituted phenyl amides from alkanes.

Polymer supported Pd catalyzed carbonylation of aryl bromides for the synthesis of aryl esters and amides

A new polymer anchored Pd(ii) Schiff base catalyst has been synthesized for the evaluation of alkoxycarbonylation and aminocarbonylation reactions of various substituted aryl bromides with alcohols and amines.

Acid-free regioselective aminocarbonylation of alkenes.

An efficient method for the synthesis of N-aryl monosubstituted carboxamides via the Pd-catalyzed carbonylation of alkenes with CO and amines is described. Mechanistic insights for this highly selective reaction are provided.

Synthesis of Biotinylated Galiellalactone Analogues

Two biotinylated derivatives of the fungal metabolite galiellalactone (1) were synthesized in order to facilitate the investigation of the molecular mechanism of action of the galiellalactonoids. Galiellalactone is a STAT3-signaling inhibitor that inhibits growth in vitro as well as in vivo of prostate cancer cells expressing activated STAT3. To provide a suitable point of attachment for biotin, the 8-hydroxymethyl derivative (3) and its 7-phenyl analogue 4 were synthesized by a modified tandem Pd-catalysed carbonylation and intramolecular vinyl allene Diels-Alder procedure previously developed. The two primary alcohols obtained, 3 and 4, were coupled to biotin as the 6-aminohexanoic acid amide, activated as the acid chloride, yielding the derivatives 5 and 6.

ChemInform Abstract: Pd(II)‐Catalyzed C(sp2)—H Carbonylation of Biaryl‐2‐amine: Synthesis of Phenanthridinones.

AbstractA novel protocol for amine directed Pd‐catalyzed carbonylation of biaryls (I) is developed.

ChemInform Abstract: Palladium‐Catalyzed Regioselective Carbonylation of C—H Bonds of N‐Alkyl Anilines for Synthesis of Isatoic Anhydrides.

A Pd-catalyzed regioselective C–H bond carbonylation of N-alkyl anilines for the synthesis of isatoic anhydrides has been developed. The key Pd-catalyst intermediate has been isolated and characterized. This novel Pd-catalyzed carbonylation reaction tolerates a wide range of functional groups and is a reliable method for the rapid elaboration of readily available N-alkyl anilines into a variety of substituted isatoic anhydrides under mild conditions.

Pd-Catalyzed Selective Carbonylative and Non-carbonylative Couplings of Propiolic Acid: One-Pot Synthesis of Diarylalkynones

Diarylalkynones were synthesized from one-pot Pd-catalyzed carbonylative and noncarbonylative coupling reactions of propiolic acid with aryl iodides under a carbon monoxide atmosphere. Aryl iodide (2.0 equiv), propiolic acid (1.0 equiv), Pd(PPh3)2Cl2 (5 mol %), CuCl (10 mol %), Et3N (6.0 equiv), and CO (8 atm) were reacted under optimized conditions in CH3CN at 80 °C for 1 h. This process afforded good yields and functional group tolerance.

Palladium-Catalyzed Synthesis of Aromatic Carboxylic Acids with Silacarboxylic Acids

Aryl iodides and bromides were easily converted to their corresponding aromatic carboxylic acids via a Pd-catalyzed carbonylation reaction using silacarboxylic acids as an in situ source of carbon monoxide. The reaction conditions were compatible with a wide range of functional groups, and with the aryl iodides, the carbonylation was complete within minutes. The method was adapted to the double and selective isotope labeling of tamibarotene.

Synthesis of Novel Aryl and Heteroaryl Acyl Sulfonimidamides via Pd-Catalyzed Carbonylation Using a Nongaseous Precursor

Hitherto unexplored aryl and heteroaryl acyl sulfonimidamides have been prepared through the development of a new Pd-catalyzed carbonylation protocol. This novel methodology, employing sulfonimidamides as nucleophiles and CO gas ex situ released from solid Mo(CO)6 in a sealed two-chamber system, yields a wide range of carbamate protected acyl sulfonimidamides in good to excellent yields.

Palladium-catalyzed synthesis of indole-3-alkynones via direct carbonylation of indoles

A new method has been developed for the Pd-catalyzed direct carbonylation of indoles with phenylacetylenes. The process involved the initial iodination of the indole to afford the corresponding 3-iodo-indole, which was subsequently carbonylated with a variety of different alkynes using Pd(0) to yield the indole-3-alkynones. In contrast to the traditional Pd-catalyzed oxidative carbonylation strategy, which involves the Pd(II)-mediated activation of the aromatic C-H bonds, the aromatic C-H bonds in the current process were activated by iodine oxidation, eliminating the problems associated with the reduction of Pd(II) to Pd(0) under the CO atmosphere. Following an extensive screening process, Pd(OAc)2/CuI was identified as the most efficient catalyst system for the reaction in the presence of a base and iodine as an oxidant under mild conditions (0.2 MPa CO, 90 °C). The reaction provided the desired products in moderate to excellent isolated yields (up to 94%) and good tolerance to a variety of different functional groups. The structure of a representative alkynone product (3he) was unambiguously verified by X-ray single crystal structure analysis. Furthermore, the carbonylation products underwent a three-component reaction with sodium azide and benzyl bromide to give the corresponding 1,2,3-triazole analogues in the absence of any catalyst, thus expanding the synthetic application of the current methodology. 采用共合成法制备了一系列不同硅氨基含量的介孔氧化硅 SBA-15, 在其孔道中引入 Keggin 型钨磷酸, 且其含量随硅氨基含量的增加而增加. 考察了不同处理温度下杂多酸的热稳定性, 发现焙烧后钨物种能在 SBA-15 孔道内高度分散. 以 H2O2 为氧化剂, 研究了该催化剂在环己烯环氧化反应中的催化活性, 考察了杂多酸负载量和焙烧温度对催化活性的影响. 结果表明, 400 °C 处理后的钨磷酸催化剂具有高的反应活性和重复使用性能.

Regio- and stereoselective trans-silylvinylation of internal alkynes catalyzed by RuHCl(CO)(PCy3)2

We report a novel trans-silylvinylation of internal alkynes catalyzed by RuHCl(CO)(PCy3)2. This method represents a highly regio- and stereoselective synthesis of functionalized dienes by means of an efficient tandem alkyne trans-silylruthenation, followed by an addition to acrylates. The products are further transformed by Pd-catalyzed cross couplings and carbonylations to afford dienes with significantly increased molecular complexity.

Palladium-Catalyzed Regioselective Carbonylation of C–H Bonds of N-Alkyl Anilines for Synthesis of Isatoic Anhydrides

A Pd-catalyzed regioselective C-H bond carbonylation of N-alkyl anilines for the synthesis of isatoic anhydrides has been developed. The key Pd-catalyst intermediate has been isolated and characterized. This novel Pd-catalyzed carbonylation reaction tolerates a wide range of functional groups and is a reliable method for the rapid elaboration of readily available N-alkyl anilines into a variety of substituted isatoic anhydrides under mild conditions.

Trichlorophenyl Formate: Highly Reactive and Easily Accessible Crystalline CO Surrogate for Palladium-Catalyzed Carbonylation of Aryl/Alkenyl Halides and Triflates

The high utility of 2,4,6-trichlorophenyl formate, a highly reactive and easily accessible crystalline CO surrogate, is demonstrated. The decarbonylation with NEt(3) to generate CO proceeded rapidly at rt, thereby allowing external-CO-free Pd-catalyzed carbonylation of aryl/alkenyl halides and triflates. The high reactivity of the CO surrogate enabled carbonylation at rt and significantly reduced the quantities of formate to near-stoichiometric levels. The obtained trichlorophenyl esters can be readily converted to a variety of carboxylic acid derivatives in high yields.

ChemInform Abstract: A General Synthesis of Indole‐3‐carboxylic Esters by Palladium‐Catalyzed Direct Oxidative Carbonylation of 2‐Alkynylaniline Derivatives.

A general synthesis of indole-3-carboxylic esters by direct Pd-catalyzed oxidative carbonylation of readily available 2-alkynylaniline derivatives is reported. In particular, 2-alkynylanilines bearing an internal triple bond and a secondary amino group (1) were directly converted into indole-3-carboxylic esters 2 in fair to good yields (50–84 %) when let to react with CO, O2, and an alcohol in the presence of the PdI2/KI catalytic system, under relatively mild conditions [100 °C and 20 atm (at 25 °C) of a 4:1 mixture CO/air]. On the other hand, under similar conditions, but in the presence of HC(OMe)3, 2-alkynylanilines bearing an internal triple bond and a primary amino group (7) afforded 1-(dimethoxymethyl)indole-3-carboxylic esters 9 through the intermediate formation of N-(dimethoxymethyl)-2-alkynylaniline derivatives II. Compounds 9 could be conveniently converted into N-unsubstituted indole-3-carboxylic esters 10 by a simple acidic treatment carried out in MeOH/H2O at 80 °C.

Synthesis of Unprotected Carboxy Indazoles via Pd-Catalyzed Carbonylation

The first published synthesis of unprotected carboxy indazoles from the corresponding bromoindazoles is described. This is achieved via Pd(II)-catalyzed carbonylation and is demonstrated to work on a variety of indazoles.

Synthesis of Benzoylacetonitriles from Pd-Catalyzed Carbonylation of Aryl Iodides and Trimethylsilylacetonitrile

Palladium-catalyzed carbonylation of aryl iodides and trimethylsilylacetonitrile to produce benzoylacetonitrile derivatives through a one-pot, three-component reaction is described. This preparation method provides good yields of the carbonylated products without any additional ligands. It has a broad substrate scope with a high tolerance for a variety of functional groups.

Carboxylic acid anhydrides viaPd-catalyzed carbonylation of aryl halides at atmospheric CO pressure

A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides via Pd-catalyzed carbonylation under atmospheric CO pressure.

Pd-catalyzed domino carbonylative–decarboxylative allylation: an easy and selective monoallylation of ketones

In the presence of an allyl alcohol, α-chloroacetophenones undergo an allyloxycarbonylation reaction followed by in situ decarboxylative allylation to selectively afford the corresponding monoallylated ketones via a Pd-catalyzed domino sequence. The scope of the reaction was extended to substituted α-chloroacetophenones as well as various allyl alcohols.

A phosphine-free Pd catalyst for the selective double carbonylation of aryl iodides

The first phosphine-free Pd-catalysed double carbonylation of aryl iodides is reported as a general and practical method, giving excellent conversions and selectivities for a wide range of aryl iodides and amine nucleophiles under atmospheric CO pressure.

Carbonylation of Nitrobenzene in Methanol with Palladium Bidentate Phosphane Complexes: An Unexpectedly Complex Network of Catalytic Reactions, Centred around a Pd–imido Intermediate

The reactivity of palladium complexes of bidentate diaryl phosphane ligands (P(2)) was studied in the reaction of nitrobenzene with CO in methanol. Careful analysis of the reaction mixtures revealed that, besides the frequently reported reduction products of nitrobenzene [methyl phenyl carbamate (MPC), N,N'-diphenylurea (DPU), aniline, azobenzene (Azo) and azoxybenzene (Azoxy)], large quantities of oxidation products of methanol were co-produced (dimethyl carbonate (DMC), dimethyl oxalate (DMO), methyl formate (MF), H(2)O, and CO). From these observations, it is concluded that several catalytic processes operate simultaneously, and are coupled via common catalytic intermediates. Starting from a P(2)Pd(0) compound formed in situ, oxidation to a palladium imido compound P(2)Pd(II)=NPh, can be achieved by de-oxygenation of nitrobenzene 1) with two molecules of CO, 2) with two molecules of CO and the acidic protons of two methanol molecules, or 3) with all four hydrogen atoms of one methanol molecule. Reduction of P(2)Pd(II)=NPh to P(2)Pd(0) makes the overall process catalytic, while at the same time forming Azo(xy), MPC, DPU and aniline. It is proposed that the Pd-imido species is the central key intermediate that can link together all reduction products of nitrobenzene and all oxidation products of methanol in one unified mechanistic scheme. The relative occurrence of the various catalytic processes is shown to be dependent on the characteristics of the catalysts, as imposed by the ligand structure.