Aziridination of alkenes promoted by iron or ruthenium complexes

Damiano, Caterina; Intrieri, Daniela; Gallo, Emma

doi:10.1016/j.ica.2017.06.032

Cited by 41 publications

(20 citation statements)

References 85 publications

(70 reference statements)

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“…Work is currently in progress in that direction. The nature of the isoelectronic cerium(IV)-imido would also be of interest: metal imidosh ave been proposed as reactive intermediates in catalytic nitrenet ransfer and the generation of ammonia, [17] and might offer other new avenuesf or cerium catalysis.…”

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confidence: 99%

A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

Castro

Cho

et al. 2019

Chemistry A European J

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A combined experimental and theoretical investigation on the cerium(IV) oxo complex [(LOEt)2Ce(=O)(H2O)]⋅MeC(O)NH2 (1; LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) demonstrates that the intermediate spin‐state nature of the ground state of the cerium complex is responsible for the versatility of its reactivity towards small molecules such as CO, CO2, SO2, and NO. CASSCF calculations together with magnetic susceptibility measurements indicate that the ground state of the cerium complex is of multiconfigurational character and comprised of 74 % of CeIV and 26 % of CeIII. The latter is found to be responsible for its reductive addition behavior towards CO, SO2, and NO. This is the first report to date on the influence of the multiconfigurational ground state on the reactivity of a metal–oxo complex.

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confidence: 99%

A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

Castro

Cho

et al. 2019

Chemistry A European J

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“…Molecules containing an aziridine functional group are a versatile class of organic synthons due to the presence of a strained three-membered ring, which can be easily involved in ring-opening reactions and the aziridine functionality often shows interesting pharmaceutical and/or biological behaviors. Gallo and collaborators recently reviewed the most important results on the catalytic activity of iron and ruthenium porphyrin complexes in the aziridination of alkenes (Scheme 51) [105]. An interesting and straightforward two-step synthesis of N-arylaziridines starting from azides and anilines was efficiently achieved under continuous flow conditions, which was highlighted in the Gallo´s review [106].…”

Section: Catalytic Applications and Azide Transformationsmentioning

confidence: 99%

Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 1—Azides, Porphyrins and Corroles

et al. 2020

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Azides and porphyrinoids (such as porphyrin and corrole macrocycles) can give rise to new derivatives with significant biological properties and as new materials’ components. Significant synthetic approaches have been studied. A wide range of products (e.g., microporous organic networks, rotaxane and dendritic motifs, dendrimers as liquid crystals, as blood substitutes for transfusions and many others) can now be available and used for several medicinal and industrial purposes.

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“…Aziridines are important synthetic intermediates in organic synthesis, medicinal chemistry, and polymer chemistry, Catalytic approaches to their syntheses have rapidly expanded in recent years , . Transition metal‐catalyzed reactions involving nitrene transfer to alkenes have gained prominence in this regard , . Of these latter catalysts, copper(I) and silver(I) scorpionate complexes [tris(pyrazolyl)borates, (normal scorpionates, or Tp R , Scheme , top left), tris(pyrazolyl)methanes (Tpm R or C ‐scorpionates, Scheme , top right), certain C‐heteroscorpionates (Scheme , bottom left), and certain nitrogen‐confused C‐scorpionates (Scheme , bottom right)] have proven adept at catalytically affording aziridines from alkenes and various nitrene sources under mild conditions.…”

Section: Introductionmentioning

confidence: 99%

Silver(I) and Copper(I) Complexes of Semi‐Bulky Nitrogen‐Confused C‐Scorpionates

et al. 2020

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Two new sterically demanding nitrogen-confused C-scorpionate ligands with a bis(3,5-diisopropylpyrazol-1yl)methyl group bound to the 3-position of a normal pyrazole ( H L iPr2 ) or an N-toluenesulfonyl pyrazole ( Ts L iPr2 ) have been prepared. Reactions between the ligands ( x L iPr2 ) and silver trifluoromethanesulfonate, AgOTf, gave four new compounds of the types [Ag(Ts, 1b; x = H, 2b) depending on the initial metal:ligand ratio. Similarly, the reactions with [Cu(CH 3 CN) 4 ](PF 6 ) produce [a] Dr.to trap and spectroscopically characterize the nitrene intermediates {[(2-py)Bpm R3R5 ]Cu(NTs)} + in CH 2 Cl 2 at -78°C using (2-tBuSO 2 )C 6 H 4 I=NTs [34] as a soluble nitrene source. The spectroscopic and magnetic data were consistent with diamagnetic, singlet species at -78°C. Calculations showed ground state triplet but all spin states [ 1/3 Cu I -nitrene or 1/3 Cu II -N·(iminyl)] and nitrene binding modes (κ 1 N-, κ 2 N,O-) are thermally accessible. These intermediates were capable of stoichiometrically transferring a nitrene unit to a variety of substrates. Then, different {[(2-py)Bpm R3R5 ]Cu(CH 3 CN)}(PF 6 ) complexes were found to be capable catalysts for nitrene transfer to unsubstituted or p-substituted styrenes giving modest yields (> 65 %) of aziridine under mild ocnditions (PhI=NTs/CH 2 Cl 2 /295 K, 24 h).In a previous study, [27] eight complexes of the type [Ag( x L R ) n ](OTf ) (n = 1, 2 and x L R = H L, Ts L, H L*, and Ts L*) were characterized and evaluated for their ability to catalyze aziridination of styrene. Both ESI(+) MS and NMR spectroscopic studies indicated that the analytically pure [Ag( x L R ) n ](OTf ) compounds did not retain their structure in CH 3 CN rather were involved in multiple dynamic equilibria in solution. These dynamic processes remained in the fast exchange regime on the NMR timescale down to the freezing point of the solvent, thereby obfuscating structural information. These silver complexes of nitrogen-confused C-scorpionates showed no or very little capacity to participate in styrene aziridination using PhI= NTs in room temperature CH 2 Cl 2 . However, [Ag( x L R ) n ](OTf ) showed modest catalytic activity at 80°C in CH 3 CN when employing a nitrene generated in-situ from H 2 NTs and PhI(OAc). Interestingly, the bulkiest derivative [Ag( Ts L * ) 2 ](OTf ) was reported to have the highest activity giving 34 % yield of the desired N-tosyl aziridine. This observation prompted the current study to determine if further increasing steric bulk of the ligands would lead to an increase in catalytic activity of silver complexes. Herein we report on the preparation of two new semi-bulky nitrogen confused scorpionates, Ts L iPr2 and H L iPr2 and their silver(I) and copper(I) complexes. The copper(I) complexes were prepared to compare catalytic activity with their silver congeners, and possibly to demonstrate the generality of any trends in ligand sterics on catalytic activity. It was also hoped that the slower ligand exchange rates associated with the smaller copper(I) compared ...

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Aziridination of alkenes promoted by iron or ruthenium complexes

Cited by 41 publications

References 85 publications

A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 1—Azides, Porphyrins and Corroles

Silver(I) and Copper(I) Complexes of Semi‐Bulky Nitrogen‐Confused C‐Scorpionates

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