Aryl carbon–chlorine (Ar–Cl) and aryl carbon–fluorine (Ar–F) bond cleavages by rhodium porphyrins

Qian, Ying; Lee, Man Ho; Yang, Wu; Chan, Kin Shing

doi:10.1016/j.jorganchem.2015.05.039

Cited by 16 publications

(7 citation statements)

References 37 publications

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“…The neutral species Rh{κ 2 - N , N -[ArNCMeCHCMeNAr]}S x similarly gives [Rh(μ-X)Ph{κ 2 - N , N -[ArNCMeCHCMeNAr]}] 2 (X = Cl, Br; Ar = 2,6-Me 2 CH 3 ), whereas the known cation [Rh(PPh 3 ) 2 (acetone) 2 ] + promotes the chelate-assisted C–X bond activation (X = Cl, Br, I) of 2-(2-halophenyl)pyridines and 10-halobenzo[ h ]quinolines to yield 16-valence-electron five-coordinate cationic rhodium(III) monohalide compounds . Recently, the C–Cl bond cleavage of para-substituted chlorobenzenes has been also achieved with RhCl(ttp) (ttp = tetrakis-4-tolylporphyrin) through a metaloradical ipso-substitution mechanism …”

Section: Introductionmentioning

confidence: 99%

“…9 Recently, the C−Cl bond cleavage of para-substituted chlorobenzenes has been also achieved with RhCl(ttp) (ttp = tetrakis-4-tolylporphyrin) through a metaloradical ipso-substitution mechanism. 10 Pincer ligands offer thermal stability and the prevention of undesired ligand exchange and redistribution, 11 which has allowed the development of particularly relevant catalytic reactions in recent years. 12 Although these properties are notable advantages from the point of view of cross-coupling and dehalogenation catalysis, the fascination with pincer systems has scarcely reached the oxidative addition of aryl halides to rhodium.…”

Section: ■ Introductionmentioning

confidence: 99%

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Selective C–Cl Bond Oxidative Addition of Chloroarenes to a POP–Rhodium Complex

et al. 2016

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The C-Cl bond cis-oxidative addition of twelve chloroarenes including chlorobenzene, chlorotoluenes, chlorofluorobenzenes, and di-and trichlorobenzenes to RhH{xant(P i Pr 2) 2 } (1; xant(P i Pr 2) 2 = 9,9-dimethyl-4,5bis(diisopropylphosphino)xanthene) and the ability of the resulting rhodium(III) species to undergo reductive elimination reactions are reported. Complex 1 reacts with chlorobenzene to give RhHCl(C 6 H 5){xant(P i Pr 2) 2 } (2), which eliminates benzene to afford RhCl{xant(P i Pr 2) 2 } (3). On the other hand, in the presence of potassium tert-butoxide (KO t Bu), it undergoes dehydrodechlorination to yield Rh(C 6 H 5){xant(P i Pr 2) 2 } (4). The reactions of 1 with 3-and 4-chlorotoluene lead to RhHCl(C 6 H 4-3-Me){xant(P i Pr 2) 2 } (5) and RhHCl(C 6 H 4-4-Me){xant(P i Pr 2) 2 } (6), respectively. Treatment of the acetone solutions of both compounds with KO t Bu also produces their dehydrodechlorination to give Rh(C 6 H 4-3-Me){xant(P i Pr 2) 2 } (7) and Rh(C 6 H 4-4-Me){xant(P i Pr 2) 2 } (8). Chlorofluorobenzenes undergo both C-Cl oxidative addition and C-H bond activation in a competitive manner. The amount of the C-H activation product increases as fluorine and chlorine are separated. Complex 1 reacts with ortho-chlorofluorobenzene to afford the C-Cl oxidative addition product RhHCl(C 6 H 4-2-F){xant(P i Pr 2) 2 } (9). The reaction of 1 with meta-chlorofluorobenzene leads to RhHCl(C 6 H 4-3-F){xant(P i Pr 2) 2 } (10; 91%) and the C-H bond activation product Rh(C 6 H 3-2-Cl-6-F){xant(P i Pr 2) 2 } (12; 9%), whereas para-chlorofluorobenzene gives a mixture of RhHCl(C 6 H 4-4-F){xant(P i Pr 2) 2 } (13; 61%) and Rh(C 6 H 3-3-Cl-6-F){xant(P i Pr 2) 2 } (15; 39%). The addition of KO t Bu to the acetone solutions of 9, 10 and 13 produces the HCl abstraction and the formation of Rh(C 6 H 4-2-F){xant(P i Pr 2) 2 } (16), Rh(C 6 H 4-3-F){xant(P i Pr 2) 2 } (17), and Rh(C 6 H 4-4-F){xant(P i Pr 2) 2 } (18). In contrast to orthochlorofluorobenzene, 1,2-dichlorobenzene reacts with 1 to give RhHCl(C 6 H 4-2-Cl){xant(P i Pr 2) 2 } (19; 32%), Rh(C 6 H 4-2-Cl){xant(P i Pr 2) 2 } (20; 51%) and Rh(C 6 H 3-2,3-Cl 2){xant(P i Pr 2) 2 } (22; 17%). The reactions of 1 with 1,3-and 1,4-dichlorobenzene lead to the respective C-Cl bond oxidative addition products RhHCl(C 6 H 4-3-Cl){xant(P i Pr 2) 2 } (23) and RhHCl(C 6 H 4-4-Cl){xant(P i Pr 2) 2 } (24), which afford Rh(C 6 H 4-3-Cl){xant(P i Pr 2) 2 } (25) and Rh(C 6 H 4-4-Cl){xant(P i Pr 2) 2 } (26) by dehydrodechlorination with KO t Bu in acetone. Treatment of 1 with 1,2,3-, 1,2,4-and 1,3,5-trichlorobenzene leads to RhHCl(C 6 H 3-2,3-Cl 2){xant(P i Pr 2) 2 } (27), RhHCl(C 6 H 3-3,4-Cl 2){xant(P i Pr 2) 2 } (28), and RhHCl(C 6 H 3-3,5-Cl 2){xant(P i Pr 2) 2 } (29). The addition of KO t Bu to acetone solutions of 27-29 affords 22, Rh(C 6 H 3-3,4-Cl 2){xant(P i Pr 2) 2 } (30) and Rh(C 6 H 3-3,5-Cl 2){xant(P i Pr 2) 2 } (31).

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Selective C–Cl Bond Oxidative Addition of Chloroarenes to a POP–Rhodium Complex

et al. 2016

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“…4-Fluoro- and 4-chloro-substituted benzyl alcohols gave Rh III (ttp)CH 2 C 6 H 4 (4-F) ( 3b ( and Rh III (ttp)CH 2 C 6 H 4 (4-Cl) ( 3c ) in 81% and 63% yields, respectively (Table , entries 2 and 3). No C–F or C–Cl cleavage products were observed . Alkylation of Rh III (ttp)Cl ( 1 ) with 4-trifluoromethylbenzyl alcohol ( 2d ) successfully afforded Rh III (ttp)CH 2 C 6 H 4 (4-CF 3 ) ( 3d ) in 65% yield in 3 h. The reactions with benzyl alcohols bearing 4- t Bu and 4-Me substituents were completed in 2 h to give Rh III (ttp)CH 2 C 6 H 4 (4- t Bu) ( 3e ) and Rh III (ttp)CH 2 C 6 H 4 (4-Me) ( 3f ) in 81% and 63% yields, respectively (Table , entries 4 and 5).…”

Section: Resultsmentioning

confidence: 99%

Alkylation of Rhodium Porphyrin Complexes with Primary Alcohols under Basic Conditions

Bian

Tam

et al. 2019

Organometallics

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“…Cross-coupling reactions are traditionally promoted by palladium catalysts, yet cationic diphosphine rhodium complexes have been shown to be also competent catalysts for this important transformation [196]. The oxidative addition of haloarenes to rhodium complexes supported by monophosphine [197][198][199][200], diphosphine [201], pincer [202][203][204][205][206][207][208] and multidentate nitrogen ligands [209,210] has been studied in depth and is assumed to be the first important elementary step in the catalytic cycle of the Suzuki-Miyaura coupling reaction between haloarenes and arylboronic acids. Transmetallation by the nucleophilic partner and subsequent reductive elimination to generate the new C-C bond complete the cycle.…”

Section: Scheme 14mentioning

confidence: 99%

“…Very electron-rich centers are required to promote breaking of the strong C-Cl bond. The activation of halobenzenes has been documented for cationic monomeric rhodium complexes with both di- [209,210] and monophosphines [197][198][199][200]. Several species can be formed following the oxidative addition of DCM to rhodium [227,228]: such species can be mononuclear and contain a terminal CH 2 Cl group.…”

Section: Catalyst Deactivation Due To Irreversible Reactions Of the Amentioning

confidence: 99%

Activation, Deactivation and Reversibility Phenomena in Homogeneous Catalysis: A Showcase based on the Chemistry of Rhodium/Phosphine Catalysts.

et al. 2019

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In the present work, the rich chemistry of rhodium/phosphine complexes, which are applied as homogeneous catalysts to promote a wide range of chemical transformations, has been used to showcase how the in situ generation of precatalysts, the conversion of precatalysts into the actually active species, as well as the reaction of the catalyst itself with other components in the reaction medium (substrates, solvents, additives) can lead to a number of deactivation phenomena and thus impact the efficiency of a catalytic process. Such phenomena may go unnoticed or may be overlooked, thus preventing the full understanding of the catalytic process which is a prerequisite for its optimization. Based on recent findings both from others and the authors’ laboratory concerning the chemistry of rhodium/diphosphine complexes, some guidelines are provided for the optimal generation of the catalytic active species from a suitable rhodium precursor and the diphosphine of interest; for the choice of the best solvent to prevent aggregation of coordinatively unsaturated metal fragments and sequestration of the active metal through too strong metal–solvent interactions; for preventing catalyst poisoning due to irreversible reaction with the product of the catalytic process or impurities present in the substrate.

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Aryl carbon–chlorine (Ar–Cl) and aryl carbon–fluorine (Ar–F) bond cleavages by rhodium porphyrins

Cited by 16 publications

References 37 publications

Selective C–Cl Bond Oxidative Addition of Chloroarenes to a POP–Rhodium Complex

Selective C–Cl Bond Oxidative Addition of Chloroarenes to a POP–Rhodium Complex

Alkylation of Rhodium Porphyrin Complexes with Primary Alcohols under Basic Conditions

Activation, Deactivation and Reversibility Phenomena in Homogeneous Catalysis: A Showcase based on the Chemistry of Rhodium/Phosphine Catalysts.

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