Mechanism of benzene loss from Tp'Rh(H)(Ph)(CN-neopentyl) in the presence of neopentyl isocyanide. Evidence for an associatively induced reductive elimination

Jones, William D.; Hessell, Edward T.

doi:10.1021/ja00041a029

Cited by 64 publications

(46 citation statements)

References 2 publications

(7 reference statements)

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“…[34] This is not a general situation, however, and the high stability of the Ir III oxidation state is an additional important factor. Our own experience in the analogous Rh system [9e] and the results of Graham, [35] Jones, [36] Bergman [37] and co-workers for other related reactions, favour Tp'Rh I intermediates. This fact has been addressed theoretically [38] and may reflect the differences in the stability of the oxidation state for these two elements.…”

Section: Me2mentioning

confidence: 84%

C−H Bond Activation of Benzene and Cyclic Ethers by TpIrIII Species

et al. 1998

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Section: Me2mentioning

confidence: 84%

C−H Bond Activation of Benzene and Cyclic Ethers by TpIrIII Species

et al. 1998

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“…Further evidence for reversible formation of an η 2 -benzene intermediate came from the observation of scrambling in the complex Tp 0 Rh(CNR)(C 6 D 5 )H. The hydride appears in all five locations on the phenyl group at the same rate, implying that the η 2 -C 6 D 5 H complex is fluxional. Rh-phenyl rotation is hindered at room temperature, and at low T, five distinct phenyl resonances can be observed in the 1 H NMR spectrum [7].…”

Section: Hydrocarbon Activation By [Tp 0 Rh(cnr)]mentioning

confidence: 99%

The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

Jones

2015

Topics in Organometallic Chemistry

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The activation of C-H bonds by oxidative addition in about 30 different substrates has been examined with three closely related metal species, [Tp 0 RhL], where L ¼ CNneopentyl, PMe 3 , and P(OMe) 3 . Kinetic studies of the reductive elimination of R-H provided data to ascertain the relative metal-carbon bond strengths for a wide range of compounds. Trends in these bond strengths reveal that there are two classes of C-H substrates: parent hydrocarbons and substituted methanes. DFT calculations are used to support the observed trends, and some generalizations are made by comparison to other metal systems.

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“…Therefore, the attempt on direct formation of styrene from benzene and ethylene using aromatic C-H bond activation leading to C-C bond formation is a considerably attractive field, which has enough room to be developed from the industrial point of view. As described in Section 1, much work related to homogeneous C-H bond activation of aromatic compounds by discrete transition metal complexes has been reported [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Group VIII metal complexes can also be employed for olefin oxidation reactions such as Pd-catalyzed partial oxidation of ethylene, as is done in the well-known Wacker reaction to form acetaldehyde [61,62] and oxidative vinylation of acetic acid to produce vinyl acetate [63].…”

Section: Conventional Synthesis Of Styrenementioning

confidence: 99%

“…Significant efforts have been directed at homogeneous C-H bond activation of aromatic compounds by discrete transition metal complexes [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, among the numerous stoichiometric studies, relatively small numbers of organic syntheses are reported.…”

Section: Introductionmentioning

confidence: 99%

Transition metal-catalyzed olefin arylation via C–H bond activation of arenes

Matsumoto¹

2007

Catal Surv Asia

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In this article, two kinds of our transition metal-catalyzed olefin arylations are summarized and discussed. The first one is Ir-catalyzed novel anti-Markovnikov hydroarylation of olefins with benzene. Using this reaction catalyzed by [Ir(l-acac-O,O¢,C 3 )(acac-O,O¢)(acac-C 3 )] 2 (acac = acetylacetonato), 1, straight-chain alkylarenes, which were not obtainable by the conventional Friedel-Crafts aromatic alkylation with olefins, were able to be successfully synthesized directly from arenes and olefins with the higher selectivity than that of branched alkylarenes. This is the first efficient catalyst which shows the desirable high regioselectivity. The reaction of benzene with propylene gave n-propylbenzene and cumene in 61% and 39% selectivities, respectively, and the reaction of benzene and styrene afforded 1,2-diphenylethane in 98% selectivity. The reaction of alkylarene and olefin showed meta and para orientations. A wide range of olefins and arenes can be employed for the synthesis of alkylarenes. The mechanism of the reaction involves C-H bond activation of benzene by Ir center to form Ir-phenyl species. The second reaction is Rh-catalyzed oxidative arylation of ethylene with benzene to directly produce styrene, namely one-step synthesis of styrene. The reaction of benzene with ethylene catalyzed by Rh(ppy) 2 (OAc) (ppyH = 2-phenylpyridine, OAc = acetate), 3 with Cu oxidizing agent gave styrene and vinyl acetate in 77% and 23% selectivities, respectively, in contrast to those by Pd(OAc) 2 , 47% of styrene and 53% of vinyl acetate. The mechanism of the reaction involves Rh-mediated C-H bond activation of benzene, which appears to be a rate-determining step. Furthermore, Rh complexes in a Rh(I) oxidation state at the beginning of the reaction work as catalysts for the reaction by addition of acacH and O 2 without any oxidizing agent, like Cu salt.

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Mechanism of benzene loss from Tp'Rh(H)(Ph)(CN-neopentyl) in the presence of neopentyl isocyanide. Evidence for an associatively induced reductive elimination

Cited by 64 publications

References 2 publications

C−H Bond Activation of Benzene and Cyclic Ethers by TpIrIII Species

C−H Bond Activation of Benzene and Cyclic Ethers by TpIrIII Species

The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

Transition metal-catalyzed olefin arylation via C–H bond activation of arenes

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