Insertion Reactions on Carbopalladated Benzyne: From Eight- to Nine- and Ten-Membered Palladacycles. Applications to the Synthesis of N-Heterocycles

Oliva-Madrid, María-José; Garcı́a-López, José-Antonio; Saura‐Llamas, Isabel; Bautista, Delia; Vicente, José

doi:10.1021/om500772p

Cited by 31 publications

(11 citation statements)

References 147 publications

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“…Our goal was the isolation of any of the organometallic intermediates arising from the insertion of unsaturated coupling partners, such as benzyne, alkynes, carbon monoxide, and isocyanides, into either of the two Pd–C bonds present in 4a . Vicente’s group reported the isolation of several aryl-Pd complexes arising from the insertion of benzyne into the Pd–C bond of six-membered palladacycles . Following a similar method, we set the reaction of 4a with benzyne generated in situ at room temperature, but even under these mild conditions the organic product 7 (arising from the C–C coupling) was detected: that is, the plausible organometallic intermediate arising from the insertion of the aryne decomposed rapidly (Scheme ).…”

Section: Resultsmentioning

confidence: 92%

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

et al. 2017

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We have studied the possible reaction pathways operating in the Pd-catalyzed remote C−H functionalization of N-(2-haloaryl)acrylamides from an organometallic approach. We have isolated and characterized several proposed reaction intermediates, such as σ-alkyl-Pd complexes and spiro C,Cpalladacycles, and evaluated the role of the base and the auxiliary ligands coordinated to Pd in the remote C−H activation process. In addition, the reactivity of these intermediates toward different unsaturated species such as benzyne, alkynes, and isocyanides has been studied in order to gain further insight into the reaction mechanism leading to functionalized spiro-oxoindoles.

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Section: Resultsmentioning

confidence: 92%

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

et al. 2017

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“…Insertion of one molecule of the alkene into the Pd–C bond of the starting palladacycle ( a or b ) would afford the 10-membered alkyl palladacycle I . For this intermediate, we propose that the R′ group is at the carbon atom bonded to Pd(II), because (1) this is the regiochemistry that explains the formation of the allyl moiety coordinated to Pd(II) in complexes 1a , b and 2a , b and (2) this is the most frequent regioisomer found in the insertion of electron-poor alkenes into the Pd–C bonds of neutral complexes. , Intermediate I could undergo β-hydride elimination to give the cisoid -(diene)PdH species II . Syn addition of Pd–H to the alkene moiety with regioselectivity in contrast with its previous elimination results in the formation of the η 3 -allyl complex anti - 1 or anti - 2 (Scheme ), which seems to be formed preferentially as the kinetic product.…”

Section: Resultsmentioning

confidence: 99%

“…While catalytic conditions make difficult the aforementioned control of the selectivity, stoichiometric reactions can offer the advantage of stepwise insertion paths for the synthesis of valuable organic products. − …”

Section: Introductionmentioning

confidence: 99%

Sequential Insertion of Alkynes, Alkenes, and CO into the Pd–C Bond of ortho-Palladated Primary Phenethylamines: from η³-Allyl Complexes and Enlarged Palladacycles to Functionalized Arylalkylamines

et al. 2021

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The eight-membered metallacycles arising from the insertion of 1 equiv of alkyne into the Pd–C bond of ortho -metalated homoveratrylamine and phentermine can further react with alkenes to give two different types of mononuclear complexes depending on the nature of the olefin. When terminal alkenes (styrene and ethyl acrylate) are used, a mixture of the anti / syn η 3 -allyl Pd(II) complexes are isolated, which evolve slowly to the syn isomers by heating the mixtures appropriately. These η 3 -allyl Pd(II) complexes do not react with CO or weak bases, but when they are treated with a strong base, such as KO t Bu, they afford Pd(0) and the functionalized starting phenethylamines containing a 1,3-butadienyl substituent in an ortho position. When 2-norbornene was used instead of terminal alkenes, the strained olefin inserts into the alkenyl Pd(II) complex to afford a 10-membered norbornyl palladium(II) complex, in which the new C , N -chelate ligand is coordinated to the metal through an additional double bond, occupying three coordination positions. The reactivity of these norbornyl complexes depends on the substituents on the inserted alkenyl fragment, and thus they can further react with (1) KO t Bu, to give Pd(0) and a tetrahydroisoquinoline nucleus containing a tricyclo[3.2.1]octyl ring, or (2) CO and TlOTf, to afford Pd(0) and amino acid derivatives or the corresponding lactones arising from an intramolecular Michael addition of the CO 2 H group to the α,β-unsaturated ester moiety. Crystal structures of every type of compound have been determined by X-ray diffraction studies.

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“…When the iminoacyl complex 5a was treated with AgOTf (AgCF 3 SO 3 ) and heated in CHCl 3 , the double-amidinium salt 6a-Xy was obtained (69% yield; Scheme ), along with metallic palladium and AgCl. We had previously used a similar synthetic route to prepare 2-aminoisoindolinium, 3,4-dihydroisoquinolinium, hexahydro-3-benzo[ d ]azocinium, and 10-membered amidinium salts derived from 5-, 6-, , 8-, ,, and 10-membered C , N -palladacycles …”

Section: Results and Discussionmentioning

confidence: 99%

Norbornadiene as a Building Block for the Synthesis of Linked Benzazocinones and Benzazocinium Salts through Tetranuclear Carbopalladated Intermediates

et al. 2016

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The six-membered C,N-palladacycle [Pd(C,N-C 6 H 4 CH 2 CMe 2 NH 2 -2)(μ-Cl)] 2 (A) derived from phentermine reacts with norbornadiene to give a di-or tetranuclear complex arising from the double insertion of the same molecule of the strained alkene into one or two distinct Pd−aryl bonds. The tetranuclear complex has been characterized by X-ray diffraction studies and exhibits a very unusual cisoid geometry in both the disposition of the C,N-chelate ligands and the position of the palladium centers. The newly formed Pd−alkyl bonds are still reactive toward the insertion of unsaturated molecules, and the tetranuclear complex reacts with CO or isocyanides to give double benzazocinones or benzazocinium salts with a cisoid geometry, after depalladation of the corresponding organometallic intermediates which have been isolated in some cases. When the related palladacycles derived from phenethylamine or Nmethylphenethylamine are used as starting materials, polymeric compounds are obtained, from which double benzazocinones or benzazocinium salts with a transoid geometry are obtained after CO or RNC insertion and subsequent depalladation. The presence of substituents on the α-carbon atom of the chelated amine influences the regiochemistry of the double carbopalladation of the norbornadiene.

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Insertion Reactions on Carbopalladated Benzyne: From Eight- to Nine- and Ten-Membered Palladacycles. Applications to the Synthesis of N-Heterocycles

Cited by 31 publications

References 147 publications

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

Sequential Insertion of Alkynes, Alkenes, and CO into the Pd–C Bond of ortho-Palladated Primary Phenethylamines: from η³-Allyl Complexes and Enlarged Palladacycles to Functionalized Arylalkylamines

Norbornadiene as a Building Block for the Synthesis of Linked Benzazocinones and Benzazocinium Salts through Tetranuclear Carbopalladated Intermediates

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Insertion Reactions on Carbopalladated Benzyne: From Eight- to Nine- and Ten-Membered Palladacycles. Applications to the Synthesis of N-Heterocycles

Cited by 31 publications

References 147 publications

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C–H Functionalization of N-(2-Haloaryl)acrylamides

Sequential Insertion of Alkynes, Alkenes, and CO into the Pd–C Bond of ortho-Palladated Primary Phenethylamines: from η3-Allyl Complexes and Enlarged Palladacycles to Functionalized Arylalkylamines

Norbornadiene as a Building Block for the Synthesis of Linked Benzazocinones and Benzazocinium Salts through Tetranuclear Carbopalladated Intermediates

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Sequential Insertion of Alkynes, Alkenes, and CO into the Pd–C Bond of ortho-Palladated Primary Phenethylamines: from η³-Allyl Complexes and Enlarged Palladacycles to Functionalized Arylalkylamines