Preparation, structure and properties of triphenylphosphine rhodium aryloxides

Kuznetsov, Vladimir F.; Yap, Glenn P. A.; Bensimon, Corinne; Alper, Howard

doi:10.1016/s0020-1693(98)00171-6

Cited by 24 publications

(17 citation statements)

References 22 publications

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“…24 The observed chemical shifts, spinspin couplings and peak-integration ratios in the 1 H-NMR spectra of complexes 1 and 2 are well consistent with those of corresponding σ-bonding aryloxo complexes in fourcoordinated square planar geometry.…”

Section: Resultssupporting

confidence: 70%

“…24 The dissociative conversion from the σ-OAr to the π-OAr is facilitated by either an electron-rich phenolate or a less basic tertiary phosphine such as PPh 3 in the complexes.…”

Section: Resultsmentioning

confidence: 99%

“…9, 24 The phenolic proton-resonances of the π-bonding aryloxide complexes were reported to appear fairly upfield-shifted in the region of δ 4.4-5.5 in stark contrast to those of σ-bonding aryloxide complexes. 24 The observed chemical shifts, spinspin couplings and peak-integration ratios in the 1 H-NMR spectra of complexes 1 and 2 are well consistent with those of corresponding σ-bonding aryloxo complexes in fourcoordinated square planar geometry.…”

Section: Resultsmentioning

confidence: 99%

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Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Jung¹,

Park²,

Seul³

et al. 2011

Bulletin of the Korean Chemical Society

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Section: Resultssupporting

confidence: 70%

“…24 The dissociative conversion from the σ-OAr to the π-OAr is facilitated by either an electron-rich phenolate or a less basic tertiary phosphine such as PPh 3 in the complexes.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Jung¹,

Park²,

Seul³

et al. 2011

Bulletin of the Korean Chemical Society

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“…There were no new signals in the 19 F spectrum. We provisionally assign 4 as a cyclometalated phosphine complex, principally on the basis of the characteristic very low frequency phosphorus resonance. , The formation of 3b and 4 as part of a mixture, along with the incomplete nature of the reaction, has thus far prevented their further characterization.…”

Section: Resultsmentioning

confidence: 99%

Ring-Expanded N-Heterocyclic Carbene Complexes of Rhodium with Bifluoride, Fluoride, and Fluoroaryl Ligands

et al. 2012

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Thermolysis of Rh(PPh 3 ) 4 H in the presence of the sixmembered N-heterocyclic carbene 1,3-bis(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidine (6-i Pr) gave the monocarbene complex Rh(6-i Pr)-(PPh 3 ) 2 H as a 1:2 mixture of the cis-and trans-phosphine isomers 1a and 1b. This same isomeric mixture was formed as the ultimate product from treating Rh(PPh 3 ) 3 (CO)H with 6-i Pr at room temperature, although pathways involving both CO and PPh 3 loss were observed at initial times. Treatment of 1a/1b with Et 3 N•3HF generated the bifluoride complex cis-Rh(6-i Pr)(PPh 3 ) 2 (FHF) (2a), which upon stirring with anhydrous Me 4 NF was converted to the rhodium fluoride complex cis-Rh(6-i Pr)(PPh 3 ) 2 F (3a). Thermolysis of 1a/1b with C 6 F 6 resulted in C−F bond activation to afford a mixture of 3a and the pentafluorophenyl complex trans-Rh(6-i Pr)(PPh 3 ) 2 (C 6 F 5 ) (5b). Complexes 1b, 2a, 3a, and 5b were structurally characterized.

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“…The major complex, which shows three ddd multiplets at δ =29.5, 32.8, and 35.4 ppm,13 was assigned to be complex 11 12. The minor complex, which was formed as a sole product on heating complex 11 at 110 °C for 24 h, was assigned to be the cyclometalated rhodium complex 12 by the similarity of its 31 P NMR spectrum14 to that of [Rh( o ‐C 6 H 4 PPh 2 )(PPh 3 ) 2 ] 15. The formation of phenylrhodium complex 11 was not observed with the trisubstituted phenylmethanols 7 m or 8 m under the same conditions (at 110 °C for 2 h), which indicates that an efficient β‐aryl elimination that generates an aryl rhodium species is characteristic of the alkoxorhodium intermediate derived from acridinol 1 .…”

Section: Methodsmentioning

confidence: 99%

Rhodium‐Catalyzed Aryl Transfer from Trisubstituted Aryl Methanols to α,β‐Unsaturated Carbonyl Compounds

Nishimura¹,

Katoh²,

Hayashi³

2007

Angew Chem Int Ed

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In transition-metal-catalyzed organic reactions involving carbon-carbon bond formation, a carbon-metal catalyst bond is often generated by transmetalation of the organic group in an organometallic reagents. For example, in the rhodium-catalyzed conjugate arylation of electron-deficient alkenes, a wide variety of arylating reagents composed of B, Si, Zn, Sn, and Ti have been used for the formation of aryl rhodium intermediates by transmetalation (Scheme 1).[1] On the other hand, it has been recently reported that organotransition-metal species can be generated from metal alkoxides through b-hydrocarbyl elimination (Scheme 2) in some catalytic organic transformations. [2][3][4][5][6][7] As for b-aryl group elimination, Miura and co-workers disclosed that the palladium-catalyzed cross-coupling of aryl halides to give biaryls proceeds with trisubstituted aryl methanols as coupling partners.[3] They also reported the palladium-catalyzed hydroarylation of enones with trisubstituted aryl methanols, although the reaction requires severe reaction conditions (xylene, 160 8C).[3c] Recently, stoichiometric b-phenyl elimination on rhodium was reported by Hartwig and co-workers, in which rhodium tert-alkoxide complexes [Rh(OCR 2 Ph)(PEt 3 ) 3 ] generate the phenylrhodium complex [RhPh(PEt 3 ) 3 ] and the corresponding ketones under mild conditions.[8] During our efforts to realize catalytic organic transformations utilizing the b-hydrocarbyl elimination process on transition-metal alkoxides, [5b, 6a-d] we found that the acridinols 1 (Bn = benzyl), which are readily obtained by Grignard addition to 10-benzylacridin-9(10H)-one (2), are highly reactive towards b-aryl elimination on their alkoxide complexes. Herein, we describe the rhodium-catalyzed conjugate arylation of a,b-unsaturated carbonyl compounds with the trisubstituted aryl methanols 1 as aryl transfer reagents.In the first set of experiments, several types of a,asubstituted benzylalcohols were examined for their reactivity in the rhodium-catalyzed 1,4-addition to 3-nonen-2-one (3 a; Scheme 3, Table 1). In the presence of [{Rh(OH)(cod)} 2 ] (cod = cycloocta-1,5-diene) as a catalyst in toluene at 110 8C for 3 h, the starting enone 3 a was recovered intact with 2-phenyl-2-propanol (4 m), triphenylmethanol (5 m), and cyclic alcohols 6 m and 7 m.[9] The reaction of xanthenol 8 m, which has been reported to be a good phenyl donor in the palladium-catalyzed cross-coupling with aryl halides, [3a] gave the 1,4-addition product 9 am, but its yield was low (22 %; Table 1, entry 1). Acridinol 1 m was found to be much more reactive than the others towards the present rhodiumcatalyzed 1,4-addition to give 9 am in quantitative yield (Table 1, entry 2). The eliminated ketone, acridinone 2, was recovered in high yield (86 %). Scheme 1. Rhodium-catalyzed 1,4-addition of aryl organometallic reagents.Scheme 2. b-Hydrocarbyl elimination.Scheme 3. Rhodium-catalyzed conjugate arylation of a,b-unsaturated carbonyl compounds through b-aryl elimination.

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Preparation, structure and properties of triphenylphosphine rhodium aryloxides

Cited by 24 publications

References 22 publications

Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Ring-Expanded N-Heterocyclic Carbene Complexes of Rhodium with Bifluoride, Fluoride, and Fluoroaryl Ligands

Rhodium‐Catalyzed Aryl Transfer from Trisubstituted Aryl Methanols to α,β‐Unsaturated Carbonyl Compounds

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Preparation, structure and properties of triphenylphosphine rhodium aryloxides

Cited by 24 publications

References 22 publications

Palladium(II) Aryloxides of Pd(2,6-(CH2NMe2)2C6H3)(OC6H4-X-p) (X = Me, NO2): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Palladium(II) Aryloxides of Pd(2,6-(CH2NMe2)2C6H3)(OC6H4-X-p) (X = Me, NO2): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Ring-Expanded N-Heterocyclic Carbene Complexes of Rhodium with Bifluoride, Fluoride, and Fluoroaryl Ligands

Rhodium‐Catalyzed Aryl Transfer from Trisubstituted Aryl Methanols to α,β‐Unsaturated Carbonyl Compounds

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Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride

Palladium(II) Aryloxides of Pd(2,6-(CH₂NMe₂)₂C₆H₃)(OC₆H₄-X-p) (X = Me, NO₂): Synthesis, Property and Reactivity towards Diphenyliodium Chloride