Synthesis of heptamethylindenyl rhodium(III) complexes: molecular structures of [(η5-C9Me7)RhCl(µ-Cl)]2 and [(η5-C9Me7)Rh(PMe2Ph)Cl2]

Kakkar, Ashok; Stringer, Graham; Taylor, Nicholas J.; Marder, Todd B.

doi:10.1139/v95-121

Cited by 22 publications

(11 citation statements)

References 11 publications

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“…In contrast with the parent indenyl ligand (Ind), Ind* is known to adopt an η 5 coordination mode on the Rhodium metal in the ground state such as Cp* with little to no tilting of the ligand toward η 3 . 31 We observed that variation at the para and meta positions of the cyclopropene units furnish the product in good yields and excellent diastereoselectivities, regardless of the electronic nature of the substituents. The observed major diastereoisomer can be rationalized through the size of the substituents on the cyclopropane ring.…”

Section: ■ Introductionmentioning

confidence: 70%

“…While Cp t and Cp* CF3 ligands deliver promising diastereoselectivity, heptamethylindenyl ligand (Ind*) proves to be the ligand of choice providing the bicyclic product in 90% yield and 15.2:1 dr. In contrast with the parent indenyl ligand (Ind), Ind* is known to adopt an η 5 coordination mode on the Rhodium metal in the ground state such as Cp* with little to no tilting of the ligand towards η 3 31 . We observed that variation at the para and meta positions of the cyclopropene units furnish the product in good yields and excellent diastereoselectivities, regardless of the electronic nature of the substituents.…”

Section: Synthesis Of Isoquinolones Pyridones and Their Derivativesmentioning

confidence: 99%

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Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

2017

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The history of transition metal catalysis is heavily steeped in ligand design, clearly demonstrating the importance of this approach. The intimate relationship between metal and ligand can profoundly affect the outcome of a reaction, often impacting selectivity, physical properties, and the lifetime of a catalyst. Importantly, this metal-ligand relationship can provide near limitless opportunities for reaction discovery. Over the past several years, transition-metal-catalyzed C-H bond functionalization reactions have been established as a critical foundation in organic chemistry that provides new bond forming strategies. Among the d-block elements, palladium is arguably one of the most popular metals to accomplish such transformations. One possible explanation for this achievement could be the broad set of phosphine and amine based ligands available in the chemist's toolbox compatible with palladium. In parallel, other metals have been investigated for C-H bond functionalization. Among them, pentamethylcyclopentadienyl (Cp*) Rh(III) complexes have emerged as a powerful mode of catalysis for such transformations providing a broad spectrum of reactivity. This approach possesses the advantage of often very low catalyst loading, and reactions are typically performed under mild conditions allowing broad functional group tolerance. Cp*Rh(III) is considered as a privileged catalyst and a plethora of reactions involving a C-H bond cleavage event have been developed. The search for alternative cyclopentadienyl based ligands has been eclipsed by the tremendous effort devoted to exploring the considerable scope of reactions catalyzed by Cp*Rh(III) complexes, despite the potential of this strategy for enabling reactivity. Thus, ligand modification efforts in Rh(III) catalysis have been an exception and research directed toward new rhodium catalysts has been sparse. Recently, chiral cyclopentadienyl ligands have appeared allowing enantioselective Rh(III)-catalyzed C-H functionalization reactions to be performed. Alongside chiral ligands, an equally important collection of achiral cyclopentadienyl-derived ligands have also emerged. The design of this new set of ligands for rhodium has already translated to significant success in solving inherent problems of reactivity and selectivity encountered throughout the development of new Rh(III)-catalyzed transformations. This Account describes the evolution of cyclopentadienyl ligand skeletons in Rh(III)-catalysis since the introduction of pentamethylcyclopentadienyl ligands to the present. Specific emphasis is placed on reactivity and synthetic applications achieved with the new ligands with the introduction of achiral mono-, di-, or pentasubstituted cyclopentadienyl ligands exhibiting a stunning effect on reactivity and selectivity. Furthermore, an underlying question when dealing with ligand modification strategies is to explain the reason one ligand outperforms another. Conjecture and speculation abound, but extensive characterization of their steric and electronic properties has ...

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Section: ■ Introductionmentioning

confidence: 70%

Section: Synthesis Of Isoquinolones Pyridones and Their Derivativesmentioning

confidence: 99%

Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

2017

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“…Good level of diastereocontrol (8.8 : 1 dr) is achieved when tert -butyl tetramethylcyclopentadienyl 12 (Cp* t Bu ) ligand was employed (entry 6). Gratifyingly, heptamethylindenyl ligand 14 (Ind*) provides high reactivity and diastereoselectivity with 90% yield and 15.2 : 1 dr (entry 7). To demonstrate the scalability of the transformation, the reaction was performed in 2 mmol scale of substrate 1a , which gives the expected product with comparable yield and selectivity.…”

Section: Resultsmentioning

confidence: 99%

Heptamethylindenyl (Ind*) enables diastereoselective benzamidation of cyclopropenes via Rh(iii)-catalyzed C–H activation

et al. 2017

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“…The presence of the methoxy group or the 2-methyl group further decreasedt he D value (5ba vs. 5bb and 5da), which were close to the D value of the highly stable Ind* complex. [13,14] This feature predicts high stability of the indenyl complexes derived from 3bb and 3da.…”

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confidence: 99%

“…[b] Ref. [13]. ducted under air.A tt he initial stage (1-2 h), the use of 4da produced 9aa in higher yield than that of 6ba and the Cp E Rh III complex.F urthermore, the reactionu sing 4da continuously generated 9aa even at the late stage (2-18 h).…”

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confidence: 99%

Synthesis of Functionalized (η⁵‐Indenyl)rhodium(III) Complexes and Their Application to C−H Bond Functionalization

Terasawa

Shibata

Kimura

et al. 2018

Chemistry An Asian Journal

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It has been established that reductive complexation of functionalized benzofulvenes, which are readily prepared from commercially available indene and 2-methylindene, with RhCl in ethanol affords the corresponding indenyl-rhodium(III) dichlorides bearing substituents at the 1- (H or CO Et), 2- (H or Me), and 3- [CH Ph or CH (2-MeOC H )] positions. The indenyl-rhodium(III) complexes bearing one ethoxycarbonyl group showed higher thermal stability and regioselectivity than our previously reported Cp Rh complex toward the oxidative [3+2] annulation of acetanilides with internal alkynes.

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Synthesis of heptamethylindenyl rhodium(III) complexes: molecular structures of [(η⁵-C₉Me₇)RhCl(µ-Cl)]₂ and [(η⁵-C₉Me₇)Rh(PMe₂Ph)Cl₂]

Abstract: Key words: rhodium, indenyl, permethylindenyl, heptamethylindenyl, phosphine complex, X-ray structure.

Cited by 22 publications

References 11 publications

Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

Heptamethylindenyl (Ind*) enables diastereoselective benzamidation of cyclopropenes via Rh(iii)-catalyzed C–H activation

Synthesis of Functionalized (η⁵‐Indenyl)rhodium(III) Complexes and Their Application to C−H Bond Functionalization

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Synthesis of heptamethylindenyl rhodium(III) complexes: molecular structures of [(η5-C9Me7)RhCl(µ-Cl)]2 and [(η5-C9Me7)Rh(PMe2Ph)Cl2]

Abstract: Key words: rhodium, indenyl, permethylindenyl, heptamethylindenyl, phosphine complex, X-ray structure.

Cited by 22 publications

References 11 publications

Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

Electronic and Steric Tuning of a Prototypical Piano Stool Complex: Rh(III) Catalysis for C–H Functionalization

Heptamethylindenyl (Ind*) enables diastereoselective benzamidation of cyclopropenes via Rh(iii)-catalyzed C–H activation

Synthesis of Functionalized (η5‐Indenyl)rhodium(III) Complexes and Their Application to C−H Bond Functionalization

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Synthesis of heptamethylindenyl rhodium(III) complexes: molecular structures of [(η⁵-C₉Me₇)RhCl(µ-Cl)]₂ and [(η⁵-C₉Me₇)Rh(PMe₂Ph)Cl₂]

Synthesis of Functionalized (η⁵‐Indenyl)rhodium(III) Complexes and Their Application to C−H Bond Functionalization