Mehrfachbindungen zwischen Hauptgruppenelementen und übergangsmetallen

Herrmann, Wolfgang A.; Romão, Carlos C.; Kiprof, Paul; Behm, Joachim; Cook, Malcolm R.; Taillefer, Marc

doi:10.1016/0022-328x(91)80035-i

Cited by 24 publications

(12 citation statements)

References 25 publications

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“…This would, however, suggest a rhenium oxidation state of +6, which is implausible on chemical grounds. Di-μ-oxo dimers of oxorhenium(VI) centers are well-known, but they invariably have rhenium–rhenium separations of 2.61 Å, indicative of a metal–metal single bond . In contrast, di-μ-oxodirhenium(VII) dimers typically have rhenium–rhenium separations of about 3.1 Å, in much better agreement with the 3.0480(4) Å observed in fac , anti -(ONO)ReO(μ-O) 2 ReO(ONO).…”

Section: Resultsmentioning

confidence: 60%

The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides

2017

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The rhenium(V) oxo complex oxo(triphenylphosphine) (bis(3,5-di-tert-butyl-2-phenoxo)amido)rhenium(V), (ONO)ReO(PPh), reacts with molecular oxygen to give triphenylphosphine oxide and the dimeric rhenium(VII) complex fac,anti-(ONO)Re(O)(μ-O)Re(O)(ONO). The ONO ligand adopts an unusual fac geometry, presumably to maximize π donation to rhenium; strong π donation is substantiated by the intraligand bond distances (metrical oxidation state = -2.24(9)). Addition of the N-heterocyclic carbene ligand IMes to fac,anti-(ONO)Re(O)(μ-O)Re(O)(ONO) cleaves the dimer into monomeric C-symmetric fac-(ONO)ReO(IMes). The monorhenium(VII) complex is deoxygenated by PMePh to give the rhenium(V) compound (ONO)ReO(IMes), which can be independently prepared by ligand substitution of (ONO)ReO(PPh). The degree of stereochemical rigidity exhibited by the dioxo compound, as established by dynamic NMR spectroscopy, excludes the intermediacy of mer-(ONO)ReO(IMes) in this oxygen atom transfer reaction. Thus, oxygen atom transfer takes place preferentially by direct reduction of the oxorhenium(VII) moiety (classical oxygen atom transfer) rather than through initial internal electron transfer and ligand-centered reduction of an oxorhenium(V)-iminoquinone.

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Section: Resultsmentioning

confidence: 60%

The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides

2017

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“…[ CAUTION : Although we encountered no difficulties, the potentially explosive nature of organic azides should be kept in mind.] The methylrhenium trioxide was synthesized from dirhenium heptoxide and tetramethyl tin in the presence of perfluoroglutaric anhydride. − Methylene chloride was first purified and stored under argon in an amber bottle over molecular sieves. Anhydrous benzene, ethyl diazoacetate, and all of the substrates were purchased commercially.…”

Section: Methodsmentioning

confidence: 99%

“…Methylrhenium trioxide, during the relatively short period from the original report to the more convenient preparative methods now available, − already has found wide use in catalysis. The catalytic applications of MTO include the epoxidation 4 and metathesis of olefins, aldehyde olefination, dehydration of alcohols, and oxygen transfer .…”

Section: Introductionmentioning

confidence: 99%

Organic Reactions Catalyzed by Methylrhenium Trioxide: Reactions of Ethyl Diazoacetate and Organic Azides

1996

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Methylrhenium trioxide (CH 3 ReO 3 or MTO) catalyzes several classes of reactions of ethyl diazoacetate, EDA. It is the first high valent oxo complex for carbene transfer. Under mild conditions and in the absence of other substrates, EDA was converted to a 9:1 mixture of diethyl maleate and diethyl fumarate. In the presence of alcohols, R-alkoxy ethyl acetates were obtained in good yield. The yields dropped for the larger and more branched alcohols, the balance of material being diethyl maleate and fumarate. An electron-donating group in the para position of phenols favors the formation of R-phenoxy ethyl acetates. The use of EDA to form R-thio ethyl acetates and N-substituted glycine ethyl esters, on the other hand, is hardly affected by the size or structure of the parent thiol or amine, with all of these reactions proceeding in high yield. MTO-catalyzed cycloaddition reactions occur between EDA and aromatic imines, olefins, and carbonyl compounds. Three-membered ring products are formed: aziridines, cyclopropanes, and epoxides, respectively. The reactions favor the formation of trans products, and provide a convenient route for the preparation of aziridines. Intermediate carbenoid and nitrenoid species have been proposed.In the presence of an oxygen source such as an epoxide, ethyl diazoacetate and azibenzil are converted to an oxalic acid monoethyl ester and to benzil; at the same time the epoxide was converted to an olefin. These results provide further support for the proposed intermediate, a cyclic species containing Re, O, and CHCO 2 Et (or, occasionally, CPhC(O)Ph) in a three-membered ring.

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“…13 The [ReO 2 (CH 2 Bu l ) 2 (OR)] compounds decompose in room light to give a mixture o f products including [{ReO 2 (CH 2 Bu t ) 2 } 2 (ji-O)], which is better prepared by stirring [ReO 2 (CH 2 Bu t ) 2 Br(py)J with Ag 2 O, hydrolyzing [ReO 2 (CH 2 Bu t ) 2 (OBu t )], or oxidizing (9) with pyridine A f -o x i d e . Pyridine A f -o x i d e and (9) have also been used to synthesize the methyl derivative [{ReO 2 Me 2 (py)} 2 (u-O)], 45 and the preparation of a related compound (16) is shown in Scheme 6. The rhenium(VII) dioxo centers in all o f these compounds have cis-oxo ligands.…”

Section: (7)mentioning

confidence: 99%

High-valent Organorhenium Compounds

Hoffman

1995

Comprehensive Organometallic Chemistry II

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Mehrfachbindungen zwischen Hauptgruppenelementen und übergangsmetallen

Cited by 24 publications

References 25 publications

The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides

The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides

Organic Reactions Catalyzed by Methylrhenium Trioxide: Reactions of Ethyl Diazoacetate and Organic Azides

High-valent Organorhenium Compounds

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