N–N bond cleavage in diazoalkanes with a titanium alkylidene

Ito, Junichi; Crestani, Marco G.; Bailey, Brad C.; Gao, Xinfeng; Mindiola, Daniel J.

doi:10.1016/j.poly.2014.07.036

Cited by 8 publications

(6 citation statements)

References 38 publications

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“… In this type of reaction, the chlorides and the amido ligands serve as proton acceptors to deprotonate the primary amines. Other synthetic protocols employ diazoalkanes or azides …”

Section: Introductionmentioning

confidence: 99%

“…10 In this type of reaction, the chlorides and the amido ligands serve as proton acceptors to deprotonate the primary amines. Other synthetic protocols employ diazoalkanes 11 or azides. 12 Starting from these easily accessible titanium imido complexes, a wide range of spectator ligands (e.g., amides, 4,13 alcoholates, 14 cyclopentadienide, 15 cyclooctatetraenides, 16 etc.)…”

Section: ■ Introductionmentioning

confidence: 99%

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Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines

et al. 2018

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The formation of the titanocene imido complexes 2b, 4, and 5 via double N−H bond activations at ambient temperature of sterically demanding amines (2,6-diisopropylaniline, tert-butylamine) by the use of the bis(η 5 :η 1 -adamantylidenepentafulvene)titanium complex (1) has been investigated. The titanium imido complex 2b exists in equilibrium with its corresponding titanium monoamide complex 2a. The equilibrium can be shifted to the side of the imide 2b by increasing the temperature. Starting from the equilibrium 2a/2b, or the titanium imido pyridine adduct 5, a broad range of [2 + 2] cycloaddition reactions are realized. In reactions with alkynes, the regioselective formation of the azacyclobutenes 6 and 7 are observed. By using carbodiimides, asymmetric (8 and 10a) and symmetric cycloaddition products (9 and 10b) are formed. In the reaction with isocyanates, dependent on the substitution pattern of the TiNR imido unit, the CO or the CN [2 + 2] cycloaddition occurs, resulting in the N,O-bound ureato(2-) complex 11 or the N,N-bound ureato(2-) complex 13. In the presence of isocyanates and nitriles, the equilibrium 2a/2b results in ring enlargement reactions to six-membered rings (12, 14) by insertion of a second equivalent of the substrate into the Ti−N bonds.

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“… In this type of reaction, the chlorides and the amido ligands serve as proton acceptors to deprotonate the primary amines. Other synthetic protocols employ diazoalkanes or azides …”

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines

et al. 2018

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“…Second, formal hydrazonido(2-) ligands, II - V , in which the diazoalkane has been reduced by two electrons, feature M–N–N and/or N–N–C angles near 120°. The further reactivity of these systems, such as N–N and C–N cleavage, is inextricably linked with charge movement within the N 2 C moiety. Therefore, it is of interest to identify the systems in which this change of electronic structure can be modulated rationally.…”

Section: Introductionmentioning

confidence: 98%

“…There are a few systems for which both the diazoalkane adduct and the corresponding carbene complex have been synthesized and structurally characterized, and conversion from the former to the latter may be brought about by photolysis, thermolysis , or Lewis acid catalysis . There are also systems in which carbene-like reactivity has been observed from the diazoalkane adduct when it is exposed to the aforementioned conditions, although the reactive species was not isolated. However, there is a lack of guiding principles for predicting whether carbene formation will be possible from a given diazoalkane complex. This situation motivates the study of the electronic structure of diazoalkane complexes as a guide to their reactivity.…”

Section: Introductionmentioning

confidence: 99%

Iron and Cobalt Diazoalkane Complexes Supported by β-Diketiminate Ligands: A Synthetic, Spectroscopic, and Computational Investigation

et al. 2018

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Diazoalkanes are interesting redox-active ligands and also precursors to carbene fragments. We describe a systematic study of the binding and electronic structure of diphenyldiazomethane complexes of β-diketiminate supported iron and cobalt, which span a range of formal d-electron counts of 7-9. In end-on diazoalkane complexes of formally monovalent three-coordinate transition metals, the electronic structures are best described as having the metal in the +2 oxidation state with an antiferromagnetically coupled radical anion diazoalkane as shown by crystallography, spectroscopy, and computations. A formally zerovalent cobalt complex has different structures depending on whether potassium binds; potassium binding gives transfer of two electrons into the η-diazoalkane, but the removal of the potassium with crown ether leads to a form with only one electron transferred into an η-diazoalkane. These results demonstrate the influence of potassium binding and metal oxidation state on the charge localization in the diazoalkane complexes. Interestingly, none of these reduced complexes yield carbene fragments, but the new cobalt(II) complex LCoPF (L = bulky β-diketiminate) does catalyze the formation of an azine from its cognate diazoalkane, suggesting N loss and transient carbene formation.

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“…The reaction of the complex 438 with diazo compounds (e.g. 443) led to the N-N bond cleavage products, imido complex 448 and 2,2-dimethylpropionitrile(449) [889]. In the proposed mechanism the diazo compound undergoes [2+2] cycloaddition to afford the diazametallacyclobutane(444), which undergoes ring expansion, hydrogen shift with ring opening, and formation of the isomeric diazametallacycle 447, which then undergoes elimination of the nitrile and formation of the imido complex.…”

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confidence: 99%

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

Herndon

2016

Coordination Chemistry Reviews

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N–N bond cleavage in diazoalkanes with a titanium alkylidene

Cited by 8 publications

References 38 publications

Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines

Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines

Iron and Cobalt Diazoalkane Complexes Supported by β-Diketiminate Ligands: A Synthetic, Spectroscopic, and Computational Investigation

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

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N–N bond cleavage in diazoalkanes with a titanium alkylidene

Cited by 8 publications

References 38 publications

Direct Access to Titanocene Imides via Bis(η5:η1-penta-fulvene)titanium Complexes and Primary Amines

Direct Access to Titanocene Imides via Bis(η5:η1-penta-fulvene)titanium Complexes and Primary Amines

Iron and Cobalt Diazoalkane Complexes Supported by β-Diketiminate Ligands: A Synthetic, Spectroscopic, and Computational Investigation

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

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Product

Resources

About

Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines

Direct Access to Titanocene Imides via Bis(η⁵:η¹-penta-fulvene)titanium Complexes and Primary Amines