Palladium in some selective oxidation reactions

Baeckvall, Jan E.

doi:10.1021/ar00093a004

Cited by 275 publications

(77 citation statements)

References 51 publications

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“…It also lent weight to Bäckvalls earlier proposal of palladium(IV) intermediates in stoichiometric oxidation reactions of alkenes. [48] In an extension of their studies on aromatic CÀH functionalization, [21] Sanford and co-workers described several examples of CÀO bond formation as a result of aliphatic C À H activation. [21,49] These reactions again rely on metalcoordinating groups for regioselective C À H activation at a Pd II center prior to metal oxidation with PhI(OAc) 2 .…”

Section: Alkyl Oxygenationmentioning

confidence: 99%

High‐Oxidation‐State Palladium Catalysis: New Reactivity for Organic Synthesis

Muñiz

2009

Angew Chem Int Ed

506

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Recent years have seen the rapid development of a new field of palladium catalysis in organic synthesis. This chemistry takes place outside the usually encountered Pd(0)/Pd(II) cycles. It is characterized by the presence of strong oxidants, which prevent further palladium(II)-promoted reactions at a given point of the catalytic cycle by selective metal oxidation. The resulting higher-oxidation-state palladium complexes have been used to develop a series of new synthetic transformations that cannnot be realized within conventional palladium catalysis. This type of catalysis by palladium in a higher oxidation state is of significant synthetic potential.

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Section: Alkyl Oxygenationmentioning

confidence: 99%

High‐Oxidation‐State Palladium Catalysis: New Reactivity for Organic Synthesis

Muñiz

2009

Angew Chem Int Ed

506

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“…[4,5] An important point regarding the nucleophilic addition is the stereochemistry of the process. [6,7] The nucleophile can coordinate to the metal center and then migrate to the coordinated double bond (insertion of olefinic bond into the palladium-nucleophile bond) or the nucleophile may attack the coordinated olefin on the face opposite to that of the metal (trans attack). [6,8] We recently reported on an intramolecular palladium(ii)-catalyzed reaction of allenic conjugated dienes involving carbon ± carbon bond formation between the allene and diene moieties.…”

Section: Introductionmentioning

confidence: 99%

“…[6,7] The nucleophile can coordinate to the metal center and then migrate to the coordinated double bond (insertion of olefinic bond into the palladium-nucleophile bond) or the nucleophile may attack the coordinated olefin on the face opposite to that of the metal (trans attack). [6,8] We recently reported on an intramolecular palladium(ii)-catalyzed reaction of allenic conjugated dienes involving carbon ± carbon bond formation between the allene and diene moieties. [9] Several mechanisms were proposed as likely pathways and one of the mechanisms considered involves trans nucleophilic attack by the allene on a (p-diene)palladium(ii) complex.…”

Section: Introductionmentioning

confidence: 99%

Allenes as Carbon Nucleophiles in Intramolecular Attack on (π‐1,3‐Diene)palladium Complexes: Evidence for trans Carbopalladation of the 1,3‐Diene

Dorange

Löfstedt

Närhi

et al. 2003

Chemistry A European J

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Reaction of allene-substituted cyclohexa- and cyclohepta-1,3-dienes with [PdCl(2)(PhCN)(2)] gave eta(3)-(1,2,3)-cyclohexenyl- and eta(3)-(1,2,3)-cycloheptenylpalladium complexes, respectively, in which C-C bond formation between the allene and the 1,3-diene has occurred. Analysis of the (pi-allyl)palladium complexes by NMR spectroscopy, using reporter ligands, shows that the C-C bond formation has occurred by a trans carbopalladation involving nucleophilic attack by the middle carbon atom of the allene on a (pi-diene)palladium(II) complex. The stereochemistry of the (pi-allyl)palladium complexes was confirmed by benzoquinone-induced stereoselective transformations to allylic acetates.

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“…[7][8][9][10] The processes have been shown to proceed by attack of nucleophiles on intermediate h 3 -allylpalladium(II) complexes generated by oxidative addition of allylic compounds including halides, [11][12][13] esters, [14][15][16][17][18][19][20][21][22][23][24][25][26] carbonates, [27][28][29][30][31][32][33][34][35][36] carbamates, [37][38][39] phosphates, [40][41][42] and related derivatives [43][44][45][46][47][48][49] to a Pd(0) complex. Because these substrates are synthesized from the corresponding allylic alcohols, palladium-catalyzed conversion of allylic alcohols directly into allylation products are highly desirable, especially from the viewpoint of the atom economy.…”

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confidence: 99%

“…4-Cyanoaniline (1f) also gave monoand diallylated products in high yields (entry 15). Using cinnamyl alcohol (2b) as allylating agent worked well with acidic and less nucleophilic anilines (entries, 2,5,8,11,13,15). The sterically more demanding 2-cyclohexenol (2c), was an inefficient allylation reagent for 1a and for the more acidic anilines, although at reflux temperature (entries 3,6,9,12,14,16).…”

mentioning

confidence: 99%

Palladium-Catalyzed Allylation of Acidic and Less Nucleophilic Anilines Using Allylic Alcohols Directly

Hsu

Gan

Yang

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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A principal goal of organometallic chemistry is the catalytic synthesis of organic compounds by using the chemistry of organic ligands covalently bound to transition metals. Most organometallic chemistry has focused on complexes with covalent metal-carbon or metal-hydrogen bonds. Transition metals have been workhorse elements in many commercialized catalytic processes that include hydrogenations, hydroformylations, acetic acid production, and other C-C and C-H bond forming processes. [1][2][3][4][5] Although carbon-oxygen, carbon-nitrogen, or carbon-sulfur bonds are found in the majority of important organic molecules, catalytic organometallic reaction chemistry that leads to the formation of carbon-heteroatom bonds is less common than that forming carbon-carbon and carbon-hydrogen bonds. Transition metal h 3 -allyl complexes, as well as transition metal s-alkyl complexes, play important roles as active species and key intermediates in many reactions catalyzed by transition metal complexes.6) The palladium-catalyzed allylation is an established, efficient, and highly stereo-and chemoselective method for C-C, C-N, and C-O bond formation, which has been widely applied to organic chemistry. [7][8][9][10] The processes have been shown to proceed by attack of nucleophiles on intermediate h 3 -allylpalladium(II) complexes generated by oxidative addition of allylic compounds including halides, [11][12][13] esters, [14][15][16][17][18][19][20][21][22][23][24][25][26] carbonates, [27][28][29][30][31][32][33][34][35][36] carbamates, [37][38][39] phosphates, [40][41][42] and related derivatives [43][44][45][46][47][48][49] to a Pd(0) complex. Because these substrates are synthesized from the corresponding allylic alcohols, palladium-catalyzed conversion of allylic alcohols directly into allylation products are highly desirable, especially from the viewpoint of the atom economy. 50,51) For achieving the palladium-catalyzed C-O bond cleavage of allylic alcohols, various other processes to facilitate the bond cleavage have been reported. 52) These processes include conversion of allylic alcohols into the esters of inorganic acids (e.g., SnCl 2 61-64) ). However, there have been only limited and sporadic reports dealing with the direct cleavage of the C-O bond in allylic alcohols on interaction with a transition metal complex. [65][66][67][68][69][70][71][72] Successful applications using allylic alcohols directly in catalytic processes are even more limited. This apparently stems from the poor capability of a nonactivated hydroxyl to serve as a leaving group. 59,60) We have recently reported our attempts and some successful applications of a process involving the C-O bond cleavage with direct use of allylic alcohols catalyzed by palladium complexes. [73][74][75][76] Herein, we report the application of this methodology to the palladium-catalyzed allylation of acidic and less nucleophilic anilines 77-80) using allylic alcohols directly. The allylation process is straightforward. We studied the reactions of acidic and less nucl...

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Palladium in some selective oxidation reactions

Cited by 275 publications

References 51 publications

High‐Oxidation‐State Palladium Catalysis: New Reactivity for Organic Synthesis

High‐Oxidation‐State Palladium Catalysis: New Reactivity for Organic Synthesis

Allenes as Carbon Nucleophiles in Intramolecular Attack on (π‐1,3‐Diene)palladium Complexes: Evidence for trans Carbopalladation of the 1,3‐Diene

Palladium-Catalyzed Allylation of Acidic and Less Nucleophilic Anilines Using Allylic Alcohols Directly

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