Cleavage of the Calkyl−Caryl Bond of [Pd−CH2CMe2Ph] Complexes

Cámpora, Juan; Gutiérrez‐Puebla, Enrique; López, Jörge A.; Monge, Ángeles; Palma, Pilar; Rı́o, Diego del; Carmona, Ernesto

doi:10.1002/1521-3757(20011001)113:19<3753::aid-ange3753>3.0.co;2-f

Cited by 49 publications

(50 citation statements)

References 38 publications

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“…The corresponding resonances for 6 are observed at more downfield positions ( δ =3.36 and 3.50 ppm). As in the case of Pd–CH 2 CMe 2 Ph complexes,29 treatment of 5 with bases resulted in orthometalation of the neophyl ligand. The cyclometalated compound [{Ir(dtbpy)(CH 2 CMe 2 C 6 H 4 )} 2 (μ‐Cl) 2 ] ( 7 ) was most conveniently prepared by treatment of 5 with Li[BEt 3 H].…”

Section: Resultsmentioning

confidence: 87%

Iridium(III) Silyl Alkyl and Iridacyclic Compounds Supported by 4,4′‐Di‐tert‐butyl‐2,2′‐bipyridyl

Lee

Williams

et al. 2006

Chemistry A European J

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Treatment of IrCl(3)x H(2)O with one equivalent of 4,4'-di-tert-butyl-2,2'-bipyridyl (dtbpy) in N,N-dimethylformamide (dmf) afforded [IrCl(3)(dmf)(dtbpy)] (1). Alkylation of 1 with Me(3)SiCH(2)MgCl resulted in C--Si cleavage of the Me(3)SiCH(2) group and formation of the Ir(III) silyl dialkyl compound [Ir(CH(2)SiMe(3))(dtbpy)(Me)(SiMe(3))] (2), which reacted with tBuNC to afford [Ir(tBuNC)(CH(2)SiMe(3))(dtbpy)(Me)(SiMe(3))] ([2(tBuNC)]). Reaction of 2 with phenylacetylene afforded dimeric [{Ir(C[triple chemical bond]CPh)(dtbpy)(SiMe(3))}(2)(mu-C[triple chemical bond]CPh)(2)] (3), in which the bridging PhC[triple chemical bond]C(-) ligands are bound to Ir in a mu-sigma:pi fashion. Alkylation of 1 with PhMe(2)CCH(2)MgCl afforded the cyclometalated compound [Ir(dtbpy)(CH(2)CMe(2)C(6)H(4))(2-C(6)H(4)CMe(3))] (4), which features an agostic interaction between the Ir center and the 2-tert-butylphenyl ligand. The cyclic voltammogram of 4 in CH(2)Cl(2) shows a reversible Ir(IV)-Ir(III) couple at about 0.02 V versus ferrocenium/ferrocene. Oxidation of 4 in CH(2)Cl(2) with silver triflate afforded an Ir(IV) species that exhibits an anisotropic electron paramagnetic resonance (EPR) signal in CH(2)Cl(2) glass at 4 K with g( parallel)=2.430 and g( perpendicular)=2.110. Protonation of 4 with HCl and p-toluenesulfonic acid (HOTs) afforded [{Ir(dtbpy)(CH(2)CMe(2)Ph)Cl}(2)(mu-Cl)(2)] (5) and [Ir(dtbpy)(CH(2)CMe(2)Ph)(OTs)(2)] (6), respectively. Reaction of 5 with Li[BEt(3)H] gave the cyclometalated complex [{Ir(dtbpy)(CH(2)CMe(2)C(6)H(4))}(2)(mu-Cl)(2)] (7). Reaction of 4 with tetracyanoethylene in refluxing toluene resulted in electrophilic substitution of the iridacycle by C(2)(CN)(3) with formation of [Ir(dtbpy)(CH(2)CMe(2)C(6)H(3){4-C(2)(CN)(3)})(2-C(6)H(4)CMe(3))] (8). Reaction of 4 with diethyl maleate in refluxing toluene gave the iridafuran compound [Ir(dtbpy)(CH(2)CMe(2)C(6)H(4)){kappa(2)(C,O)-C(CO(2)Et)CH(CO(2)Et)}] (9). Treatment of 9 with 2,6-dimethylphenyl isocyanide (xylNC) led to cleavage of the iridafuran ring and formation of [Ir(dtbpy)(CH(2)CMe(2)C(6)H(4)){C(CO(2)Et)CH(CO(2)Et)}(xylNC)] (10). Protonation of 9 with HBF(4) afforded the dinuclear neophyl complex [(Ir(dtbpy)(CH(2)CMe(2)Ph){kappa(2)(C,O)-C(CO(2)Et)CH(CO(2)Et)})(2)][BF(4)](2) (11). The solid-state structures of complexes 2-5 and 8-11 have been determined.

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Section: Resultsmentioning

confidence: 87%

Iridium(III) Silyl Alkyl and Iridacyclic Compounds Supported by 4,4′‐Di‐tert‐butyl‐2,2′‐bipyridyl

Lee

Williams

et al. 2006

Chemistry A European J

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“…Single crystals of 4 were grown from a CH 2 Cl 2 solution lay- ered with hexane at room temperature. [22] In summary, we have succeeded in showing the first amination of aryl mesylates. The six-membered cyclometallated ring is puckered and the bite angle of C10-Pd1-P1 is 82.01(10)8.…”

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confidence: 88%

Palladium‐Catalyzed Amination of Aryl Mesylates

et al. 2008

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“…The carbonyl must become nearly perpendicular to the arene (i.e., 12 ) resulting in a loss of conjugation via an η 1 or η 2 complex. 56 …”

Section: Mechanistic Studiesmentioning

confidence: 99%

Mild Aromatic Palladium-Catalyzed Protodecarboxylation: Kinetic Assessment of the Decarboxylative Palladation and the Protodepalladation Steps

et al. 2013

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Mechanism studies of a mild palladium catalyzed decarboxylation of aromatic carboxylic acids are described. In particular, reaction orders and activation parameters for the two stages of the transformation were determined. These studies guided development of a catalytic system capable of turnover. Further evidence reinforces that the second stage, protonation of the aryl palladium intermediate, is the rate-determining step of the reaction. The first step, decarboxylative palladation is proposed to occur through an intramolecular electrophilic palladation pathway, which is supported by computational and mechansim studies. In contrast to the reverse reaction (C-H insertion), the data support an electrophilic aromatic substitution mechanism involving a stepwise intramolecular protonation sequence for the protodepalladation portion of the reaction.

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Cleavage of the Calkyl−Caryl Bond of [Pd−CH2CMe2Ph] Complexes

Cited by 49 publications

References 38 publications

Iridium(III) Silyl Alkyl and Iridacyclic Compounds Supported by 4,4′‐Di‐tert‐butyl‐2,2′‐bipyridyl

Iridium(III) Silyl Alkyl and Iridacyclic Compounds Supported by 4,4′‐Di‐tert‐butyl‐2,2′‐bipyridyl

Palladium‐Catalyzed Amination of Aryl Mesylates

Mild Aromatic Palladium-Catalyzed Protodecarboxylation: Kinetic Assessment of the Decarboxylative Palladation and the Protodepalladation Steps

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