Palladium-catalyzed double carbonylation of aryl halides to give .alpha.-keto amides. Mechanistic studies

Ozawa, Fumiyuki; Soyama, Hidehiko; Yanagihara, Hisayoshi; Aoyama, Issei; Takino, H.; Izawa, Kunisuke; Yamamoto, Takakazu; Yamamoto, Akio

doi:10.1021/ja00297a033

Cited by 197 publications

(87 citation statements)

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“…Previous studies devoted to a-ketoaminocarbonylation have shown that best results are obtained with rather high basicity and bulky phosphines such as methyldiphenylphosphine and the chelating ligand diphenylphosphinobutane (dppb). [9] In the present case, virtually complete selectivity was indeed achieved when PPh 2 Me was employed but the reaction rate was low (entry 9). Much more surprisingly, the catalyst system based on dppb proved to be inefficient (entry 10).…”

Section: Synthesis Of Pyridylglyoxamidesmentioning

confidence: 57%

“…[9] Appropriate conditions for the double carbonylation of iodopyridines were first sought by using 4-iodopyridine (1) as starting material. Based on previous results regarding the reactivity of non-heteroaryl halides, [9] diethylamine was selected as the most suitable secondary amine for obtaining a-keto amides. Table 1 summarizes the performance of various catalytic systems for this reaction.…”

Section: Synthesis Of Pyridylglyoxamidesmentioning

confidence: 99%

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Catalytic Synthesis and Asymmetric Reduction of Pyridylglyoxylic Amides and Esters

et al. 2001

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The preparation of 2‐pyridyl‐ and 4‐pyridylglyoxylic esters and amides in moderate to high yields via palladium‐catalyzed double carbonylation of 2‐iodo‐ and 4‐iodopyridines is reported. The effect of temperature, CO pressure, solvent, nature and concentration of nucleophile, nature of catalyst precursor, and substituents on iodopyridines has been investigated. The reduction of 4‐pyridylglyoxylate esters into the corresponding α‐hydroxy esters via ruthenium‐catalyzed asymmetric hydrogenation or using alpine‐borane proceeded in high yields but poor enantioselectivity. The results for the carbonylation and the hydrogenation catalytic processes are discussed in terms of electronic effects induced by the pyridyl ring.

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Section: Synthesis Of Pyridylglyoxamidesmentioning

confidence: 57%

Section: Synthesis Of Pyridylglyoxamidesmentioning

confidence: 99%

Catalytic Synthesis and Asymmetric Reduction of Pyridylglyoxylic Amides and Esters

et al. 2001

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“…We also examined the effect of the amount of 1 (entries 8-10), because 1 generates CO rapidly in the reaction with DBU in toluene at 80 °C, therefore the amount of 1 affects the CO pressure inside the sealed reaction vessel. Since high CO pressure often retards the oxidative addition of bromoarenes to the Pd center due to the π-acidity of CO, 29,30) the internal CO pressure would affect the Pd-catalyzed process. Two equiv of 1 were optimal for the reaction (entry 9), and 1.5 or 3.0 equiv of 1 gave slightly lower yields of the desired ester (entries 8 and 10).…”

Section: Resultsmentioning

confidence: 99%

Palladium-Catalyzed External-CO-Free Carbonylation of Aryl Bromides Using 2,4,6-Trichlorophenyl Formate

Konishi

Sekino

Manabe

2018

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…This is an important aspect for successful carbonylation because (1) CO generation and Pd-catalyzed carbonylation are mutually independent processes, and (2) an appropriate rate of CO supply realizes the smooth promotion of the Pd-catalyzed carbonylation step because excessive ligation of CO to Pd, which retards the reaction, 76) is suppressed. Our mechanistic findings were used to improve the reaction conditions of Pd-catalyzed phenoxycarbonylations using 20a (Chart 12).…”

Section: Mechanism For the Co Generation From Phenyl Formatementioning

confidence: 99%

Creation of Novel Toxic Gas Surrogates and the Development of Safe and Facile Catalytic Reactions

Konishi

2018

CHEMICAL & PHARMACEUTICAL BULLETIN

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The use of toxic gas surrogates in organic reactions instead of the gas itself contributes to enhancing the safety, practicality, and efficiency of the reactions involved. Our efforts toward the creation of toxic gas surrogates and the development of a series of catalytic reactions using these surrogates are described. Improvements in substrate scope during the hydroesterification of alkenes using formates facilitated by the Ru-imidazole catalyst system provided the opportunity to discover that phenyl formate is a useful carbon monoxide (CO) surrogate for the generation of CO and phenol under weakly basic conditions. This discovery triggered the development of highly reactive but stable CO surrogates and a variety of Pd-catalyzed carbonylative transformations. N-Formylsaccharin facilitated the use of additional nucleophiles in carbonylation reactions that provided access to a variety of carbonyl compounds. Detailed experimental and theoretical mechanistic studies into the generation of CO from phenyl formate suggest that CO generation proceeds via a concerted E2 α-elimination. Furthermore, a known surrogate of sulfur dioxide was applied for the first time to the selective syntheses of cyclic sulfonamides and sulfinamides, confirming that the surrogate operates as an "S O" source. Notably, the reactions described herein are scalable and can be performed without the use of external toxic gases and specialized reaction vessels; they are easy and simple to perform and demonstrate enormous potential for industrial application.

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Palladium-catalyzed double carbonylation of aryl halides to give .alpha.-keto amides. Mechanistic studies

Cited by 197 publications

References 0 publications

Catalytic Synthesis and Asymmetric Reduction of Pyridylglyoxylic Amides and Esters

Catalytic Synthesis and Asymmetric Reduction of Pyridylglyoxylic Amides and Esters

Palladium-Catalyzed External-CO-Free Carbonylation of Aryl Bromides Using 2,4,6-Trichlorophenyl Formate

Creation of Novel Toxic Gas Surrogates and the Development of Safe and Facile Catalytic Reactions

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