Palladium-assisted organic reactions

Barr, Neal; Bartley, J. P.; Clark, Peter W.; Dunstan, P.O.; Dyke, S.F.

doi:10.1016/0022-328x(86)80066-3

Cited by 21 publications

(12 citation statements)

References 12 publications

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“…The reactions of palladacycles 2 and 3 with CO are related to those of cyclopalladated arylalkylamines, which may afford esters or lactams. − ,,− The lack of reactivity of the NMe 2 derivative 2c contrasts with the ability of classical cyclopalladated N , N -dialkylbenzylamines to give C–N reductive coupling products after the insertion of CO into the Pd–C bond by losing one of the alkyl groups. , …”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Ortho-Palladated 3-Phenylpropanamides. Insertion of CO, XyNC, and Alkynes into the Pd–C Bond. Synthesis of Seven- and Nine-Membered Palladacycles and Benzazepine- and Benzazonine-Based Heterocycles

et al. 2013

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Aryl palladium complexes [Pd{C 6 H 4 (CH 2 ) 2 C(O)-NRR′)-2}I(tmeda)] [NRR′ = NH 2 (1a), NHMe (1b), NMe 2 (1c); tmeda = N,N,N′,N′-tetramethylethylenediamine] are prepared by oxidative addition of the corresponding 3-(2iodophenyl)propanamides to "Pd(dba) 2 " ([Pd 2 (dba) 3 ]•dba; dba = dibenzylideneacetone) in the presence of tmeda. The cationic seven-membered palladacycles [Pd{κ 2 C,O-C 6 H 4 (CH 2 ) 2 C(O)-NRR′)-2}(tmeda)]TfO (2a−c) are obtained by reacting 1a−c with AgTfO. Neutral amidate complexes of the type [Pd{κ 2 C,N-C 6 H 4 (CH 2 ) 2 C(O)NR)-2}(tmeda)] [R = H (3a), Me (3b)] are obtained upon deprotonation of the amide function in 1a or 1b with KO t Bu. The reaction of 1a with CO at room temperature affords the stable acyl derivative [Pd{C(O)C 6 H 4 (CH 2 ) 2 C-(O)NH 2 -2}I(tmeda)] (4), while 2a gives Pd, (tmedaH)TfO, and 4,5-dihydro-2H-benzo[c]azepine-1,3-dione (5a). Compound 5a can also be obtained in high yield by treating the amidate complex 3a with CO, while a low yield of 2-methyl-4,5-dihydro-2Hbenzo[c]azepine-1,3-dione (5b) was obtained from 3b under the same conditions. Complexes 1a−c react with 3 equiv of XyNC to give trans-[Pd{C(NXy)C 6 H 4 (CH 2 ) 2 C(O)NRR′-2}I(CNXy) 2 ] [NRR′ = NH 2 (6a), NHMe (6b), NMe 2 (6c)]. By refluxing a CHCl 3 solution of 6a or 1a and XyNC in 1:1 molar ratio, mixtures of 1-(2,6-dimethylphenylimino)-1,2,4,5tetrahydrobenzo[c]azepin-3-one (7a) and 2-(2-cyanoethyl)-N-(2,6-dimethylphenyl)benzamide (8a) are obtained. Complexes 2a−c react with alkynes in 1:1 molar ratio to give nine-membered palladacycles of the type [Pd{κ 2 C,O-C(X) C(X)C 6 H 4 (CH 2 ) 2 C(O)NRR′-2}(tmeda)]TfO [NRR′ = NH 2 , X = Ph (9a), C 6 H 4 n Bu-4 (10a), C 6 H 4 Br-4 (11a), CO 2 Me (12a); NRR′ = NHMe, X = Ph (9b); NRR′ = NMe 2 , X = Ph (9c)]. The reaction of 2a with an excess of 3-hexyne gives the complex [Pd{η 3 -C 6 H 4 (C 4 Et 4 )(CH 2 ) 2 C(O)NH 2 }(tmeda)]TfO (13), containing a spirocyclic ligand coordinated to Pd through a η 3 -allylic bond. The derivatives 9a, 10a and 11a react with CO at 50 °C in CHCl 3 to give colloidal Pd, (tmedaH)TfO, and the corresponding 6,7-disubstituted 1,2-dihydro-4H-benzo[e]azonine-3,5-diones (14, 15, 16), which result from a CO insertion/C− N reductive coupling sequence.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Ortho-Palladated 3-Phenylpropanamides. Insertion of CO, XyNC, and Alkynes into the Pd–C Bond. Synthesis of Seven- and Nine-Membered Palladacycles and Benzazepine- and Benzazonine-Based Heterocycles

et al. 2013

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“…Complexes 2a or 2b react with CO at 65 °C or room temperature, respectively, to afford Pd(0) and the corresponding tetrahydrobenzazocinones 4a or 4b (Scheme ), respectively. Formation of these lactams can be explained according to the generally accepted mechanism for the insertion of CO into the Pd–C bond of five- and six-membered palladacycles, ,, that is, (1) coordination of CO to the metal center, (2) migratory insertion of the organyl group to the coordinated CO, and (3) depalladation of the acyl complex through a C–N coupling. Lactam 4b2 can be obtained in better yield by reacting the previously reported mononuclear derivative 3b2 with CO in the presence of TlOTf (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Reactivity toward CO of Eight-Membered Palladacycles Derived from the Insertion of Alkenes into the Pd–C Bond of Cyclopalladated Primary Arylalkylamines of Pharmaceutical Interest. Synthesis of Tetrahydrobenzazocinones, Ortho-Functionalized Phenethylamines, Ureas, and an Isocyanate

et al. 2012

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The ortho-metalated complex [Pd{C,N-C6H2CH2CH2NH2-2,(OMe)2-4,5}(μ-Br)]2 (1a) derived from homoveratrylamine reacts with ethyl acrylate, methyl vinyl ketone, or 2-norbornene to give the dimeric complex arising from the insertion of the alkene into the Pd–C bond, [Pd{C,N-CH(R)CH2C6H2CH2CH2NH2-2,(OMe)2-4,5}(μ-Br)]2 (R = CO2Et (2a1), C(O)Me (2a2)) or [Pd{C,N-CH(C5H8)CHC6H2CH2CH2NH2-2,(OMe)2-4,5}(μ-Br)]2 (2a3). Complexes 2a and the phentermine homologues 2b react with CO to afford Pd(0) and (1) tetrahydrobenzazocinones, the heterocycles resulting from CO insertion into the Pd–C bond and C–N coupling, (2) unnatural amino acid derivatives, resulting from CO insertion and the reaction of the obtained acyl complex with the solvent (MeOH), or the product of protonolysis of the Pd–C bond, depending on the nature of the initial cyclopalladated compound, or (3) ureas, alone or mixed with an isocyanate, in the presence of a base. Phentermine derivatives 2b react with HCl to give a dinuclear palladium complex [PdCl(μ-Cl)(L)], where L is the amine arising from the protonolysis of the Pd–C bond or the alkyl group resulting from Pd–N bond protonolysis, depending on the nature of the inserted alkene. The crystal structures of some palladium complexes and organic compounds have been determined by X-ray diffraction studies.

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“…When the analogous reactions were carried out with complexes 3c and 3d , the tetrahydroisoquinolines 5c and 5d formed. They must arise from the intramolecular hydroamination of the 2-vinylated phenethylamine, as its double bond is activated by the presence of an electron-withdrawing group. ,, Therefore, complexes 3c and 3d contain short-lived species as ligands. Protonation of 5d with HCl afforded 5d -HCl.…”

Section: Resultsmentioning

confidence: 99%

“…When starting from ortho-palladated secondary or tertiary benzylamines, the reactions give, in most cases, Pd(0) and the products of the Heck reaction, i.e., the ortho-vinylated amines. , Instead, we report here that some olefins insert into the Pd−C bond of ortho-palladated primary amines, giving stable alkyl palladium compounds that can be decomposed to afford complexes containing the corresponding coordinated ortho-vinylated amine; when these ligands are replaced, some can be isolated, but others undergo a cyclization process through a hydroamination reaction, affording tetrahydroisoquinolines. As far as we are aware, the latter behavior has only one precedent that involve a nonisolated ortho-palladated compound …”

Section: Introductionmentioning

confidence: 99%

“…As far as we are aware, the latter behavior has only one precedent that involve a nonisolated ortho-palladated compound. 17 In this study we have used ortho-palladated complexes of the important drugs phenethylamine 18 and phentermine 19 in order to ortho-functionalize them with a vinyl group (Scheme 1). We have previously used the same or similar ortho-palladated complexes 20 of pharmaceutical products to ortho-functionalize them (with Br, 21 I 19,21 ) or to form cycles involving the ortho-carbon, an unsaturated molecule (CO, 21 RNC 22,23 ), and the nitrogen atom.…”

Section: Introductionmentioning

confidence: 99%

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Eight-Membered Palladacycles Derived from the Insertion of Olefins into the Pd−C Bond of Ortho-Palladated Pharmaceuticals Phenethylamine and Phentermine. Synthesis of Stable Heck-Type Intermediates Containing Accessible β-Hydrogens and Its Use in the Synthesis of 2-Styrylphenethylamines, Tetrahydroisoquinolines, and Eight-Membered Cyclic Amidines

et al. 2010

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The ortho-metalated complexes derived from phenethylamine and phentermine, [Pd(C,N-C 6 H 4 CH 2 -CR 2 NH 2 -2)(μ-X)] 2 (R=H, X=Br (A); R=Me, X=Cl (B)), react with olefins giving (1) the product of its insertion into the Pd- 2) the decomposition products of 1, i.e., Pd(0) and the complexes containing the arylated olefin, trans-[PdX 2 (NH 2 CR 2 CH 2 C 6 H 4 CHdCHPh-2) 2 ] (olefin = styrene; R = H, X = Br (3f ); R = Me, X = Cl (3g)). While complexes 1c and 1d can be isolated but decompose in solution to afford Pd(0) and the corresponding complexes 3 (R = H, X = Br (3c); R = Me, X = Cl (3d)), the others are surprisingly stable. Neutral ligands L cleave the bridges of complexes 1 to afford [Pd(C ∧ N)X(L)] (2) (L= 4-methylpyridine (pic), NH 3 , NHEt 2 , PPh 3 , t BuNC, XyNC). Complexes 3 react with 1,10-phenanthroline (phen) to give [PdX 2 (phen)] and the ortho-vinylated arylalkylamine RCHdCHC 6 H 4 CH 2 CR 2 NH 2 -2 (R = H (4f), Me (4g)), which in the case of 3c or 3d cannot be isolated, as it undergoes an intramolecular hydroamination process to afford the tetrahydroisoquinoline 5c or 5d, respectively. To prepare the tetrahydroisoquinoline 5b, it is necessary to heat a mixture of complex 1b with 1 equiv of TlOTf. The eight-membered cyclic amidine 7d is obtained from thermal decomposition of complex cis-[Pd{C,N-CH(CO 2 Et)CH 2 C 6 H 4 CH 2 CMe 2 NH 2 -2}(CNXy) 2 ]OTf (8d), prepared by reaction of 2d-5 with TlOTf and XyNC. The amidinium salt 7e-HOTf is formed by refluxing in toluene a mixture of 2e-4 and TlOTf. The crystal structures of compounds 2a 3 CHCl 3 , 2b-1, 2d-3 3 1/3CH 2 Cl 2 , 2e-4 3 1/ 2CHCl 3 , 3d, 3g, 6, and 7e-HOTf have been determined by X-ray diffraction studies. † Dedicated to Profs. Aurelia Arcas and Maria-Teresa Chicote on the occasion of their 60th birthdays.

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Palladium-assisted organic reactions

Cited by 21 publications

References 12 publications

Synthesis and Reactivity of Ortho-Palladated 3-Phenylpropanamides. Insertion of CO, XyNC, and Alkynes into the Pd–C Bond. Synthesis of Seven- and Nine-Membered Palladacycles and Benzazepine- and Benzazonine-Based Heterocycles

Synthesis and Reactivity of Ortho-Palladated 3-Phenylpropanamides. Insertion of CO, XyNC, and Alkynes into the Pd–C Bond. Synthesis of Seven- and Nine-Membered Palladacycles and Benzazepine- and Benzazonine-Based Heterocycles

Reactivity toward CO of Eight-Membered Palladacycles Derived from the Insertion of Alkenes into the Pd–C Bond of Cyclopalladated Primary Arylalkylamines of Pharmaceutical Interest. Synthesis of Tetrahydrobenzazocinones, Ortho-Functionalized Phenethylamines, Ureas, and an Isocyanate

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