Stereodynamics and conformational equilibria in some chiral pseudo-octahedral tungsten crotyl complexes

Faller, J. W.; Fontaine, Philip P.

doi:10.1016/j.jorganchem.2006.07.037

Cited by 3 publications

(5 citation statements)

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“…Transition metal catalyzed allylic substitution with carbon nucleophiles is a powerful carbon–carbon bond-forming reaction . A number of enantioselective transformations have been realized with various transition metal catalysts including Pd, Mo, W, Ru, Rh, and Ir by employing stabilized carbon nucleophiles such as malonates. For enantioselective allylic alkylation with nonstabilized carbon nucleophiles, Cu catalyst is most frequently employed, allowing the enantioselective installation of simple alkyl groups at the allylic position …”

Section: Introductionmentioning

confidence: 99%

P-Chiral Monophosphorus Ligands for Asymmetric Copper-Catalyzed Allylic Alkylation

Xiong

et al. 2019

Organometallics

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Section: Introductionmentioning

confidence: 99%

P-Chiral Monophosphorus Ligands for Asymmetric Copper-Catalyzed Allylic Alkylation

Xiong

et al. 2019

Organometallics

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“…A spontaneous resolution of various cobalt, ruthenium, tungsten, molybdenum, cobalt, iron or zinc complexes of tetrahedral and octahedral coordination has been reported. 38–43…”

Section: Resultsmentioning

confidence: 99%

“…A spontaneous resolution of various cobalt, ruthenium, tungsten, molybdenum, cobalt, iron or zinc complexes of tetrahedral and octahedral coordination has been reported. [38][39][40][41][42][43] Also seven-coordinate lanthanides complexes of praseodymium, samarium and erbium are chiral and crystallize as conglomerates in non-centrosymmetric R3 space group. 44 The phenomenon of conglomerate crystallization was recognized in tetrahedral and octahedral metal-ligand cages.…”

Section: Crystallographic Analysismentioning

confidence: 99%

Piano-stool ruthenium(ii) complexes with maleimide and phosphine or phosphite ligands: synthesis and activity against normal and cancer cells

et al. 2023

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“…[211] The relative concentrations of each rotamer vary amongst the different complexes, most significantly with the anionic ligand, but the major isomer has invariably been established as the lower energy rotamer, D. [114] Complexes containing bidentate ligands bound via two P-donor atoms have received some attention pertaining to their unique dynamic processes and chirality. [171,216,230,232,233] The trigonal twist mechanism (vide supra), which is rapid at room temperature (ΔG ‡ ≈ 30 -45 kJ mol -1 ), has been well described for complexes [M(CO)2(η 3 -allyl)(P⏜P)X] (P⏜P = dmpm, dmpe, dppm, dppe;…”

Section: Scheme 22mentioning

confidence: 99%

“…Interestingly, the low temperature spectrum at -85 °C reveals the presence of just one diastereomer pertaining to the trigonal twist, presumably due to the reduced steric hindrance with the asymmetric allylic ligand in the preferred isomer (an analogous phenomenon to that observed in 79; Scheme 26). [216] Electronic circular dichroism measurements on the η 3 -crotyl complex [Mo(CO)2(η 3 -1-Me-allyl)(dppe)Cl] (Table 7; entry 71) have revealed that inversion at the stereogenic centre of the methyl-substituted allyl ligand also occurs (Scheme 27c), albeit much more slowly than the trigonal twist fluxionality. [230] Thus, the (R) ⇌ (S) interconversion of the η 3 -crotyl ligand is not manifested in the respective variable temperature NMR spectra, since the two (R) and (S)…”

Section: Scheme 22mentioning

confidence: 99%

η3-Allyl carbonyl complexes of group 6 metals: Structural aspects, isomerism, dynamic behaviour and reactivity

Ryan

Cardin

Hartl

2017

Coordination Chemistry Reviews

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Contents 1. Introduction 2. Complexes [CpM(CO)2(η 3 -allyl)] and related compounds 2.1. Synthetic strategies 2.2. Exo ⇌ endo isomerism 2.3. 95 Mo and 183 W NMR spectroscopy 2.4. Oxidized cationic complexes -reactivity, fluxionality, structural features 2.5. Mixed nitrosyl carbonyl complexes [CpM(CO)(NO)(η 3 -allyl)] + (M = Mo, W) 3. Complexes [M(CO)2(η 3 -allyl)(α-diimine)X] (X = anionic monodentate ligand) and related compounds 3.1. Synthetic strategies 3.2. Mechanistic features, structural aspects, and dynamic behaviour 3.3. Monodentate ligands bound to M(CO)2(η 3 -allyl)(L⏜L): reactivity and intermediacy in allylic alkylations 3.4. Redox Properties and Electrocatalysis 4. Amidinato and pyrazolato complexes related to [M(CO)2(η 3 -allyl)(α-diimine)X] 4.1. Synthesis and dynamic behaviour 4.2. Coordinatively unsaturated species and their reactivity 5. Summary and outlook Acknowledgement References 2 ABSTRACTTransition metal complexes with π-allylic ligands remain an attractive topic in organometallic chemistry, given the numerous reports of a wide variety of synthetic routes, dynamic behaviour and reactivity, structural (including isomerism), spectroscopic and redox properties, and applications in organic synthesis and catalysis. Surprisingly, despite the considerable interest in the rich and varied chemistry of this family of organometallic compounds, there is no recent review. This review is focused on π-allylic representatives of low-cost Group-6 metals bearing one or more carbonyl ligand, the coordination sphere being complemented with η 5cyclopentadienyl (Section 2), chelating ligands, including redox active α-diimines and various complementary diphosphine (Section 3) and novel anionic amidinate or pyrazolate (Section 4) ligands. In Section 1 particular attention is paid to rearrangements of the π-allylic ligand, namely exo and endo isomerism, interconversion mechanisms, fluxionality, and agostic interactions. In addition, the application of multinuclear NMR spectroscopy to the elucidation of such isomerism, and the effect of the metal centre oxidation state on the bonding, dynamic behaviour and reactivity of the π-allylic ligand are described. The detailed mechanistic description of the synthetic routes and dynamic behaviour of selected representatives of αdiimine complexes in Section 2 is followed by a description of the [M(CO)2(η 3 -allyl-H,R)(αdiimine)] 0/+ fragment as a convenient scaffold for diverse monodentate ligands participating in a range of substitution, insertion, intramolecular migration and C-C coupling reactionsfrequently involving also the π-allylic ligand, such as allylic alkylation. Special attention is devoted to selected examples of redox and acid-base reactivity of the α-diimine complexes with emphasis on prospects in electrocatalysis. The amidinate (and related pyrazolate) ligands treated in Section 4 may directly replace the π-allylic ligand in some cyclopentadienyl complexes (Section 2) or the α-diimine ligand in some dicarbonyl π-allylic complexes (Section 3). The brief description...

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Stereodynamics and conformational equilibria in some chiral pseudo-octahedral tungsten crotyl complexes

Cited by 3 publications

References 32 publications

P-Chiral Monophosphorus Ligands for Asymmetric Copper-Catalyzed Allylic Alkylation

P-Chiral Monophosphorus Ligands for Asymmetric Copper-Catalyzed Allylic Alkylation

Piano-stool ruthenium(ii) complexes with maleimide and phosphine or phosphite ligands: synthesis and activity against normal and cancer cells

η3-Allyl carbonyl complexes of group 6 metals: Structural aspects, isomerism, dynamic behaviour and reactivity

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