Nitrenium Ions

Abramovitch, R. A.; Jeyaraman, R.

doi:10.1016/b978-0-12-633480-7.50010-9

Cited by 53 publications

(37 citation statements)

References 144 publications

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“…Nitrenium ions [1][2][3] have the general formula RR'N , making them nitrogen analogs of carbenes (RR'C). The nitrenium ions differ from the more familiar nitrenes (R-N) in that they are divalent and cationic rather than univalent and neutral.…”

Section: Introductionmentioning

confidence: 99%

Singlet and triplet states in the reactions of nitrenium ions

Falvey

1999

J. Phys. Org. Chem.

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Nitrenium ions (R-N-R ) are reactive intermediates which are isoelectronic with carbenes. Like the more familiar carbenes, nitrenium ions have low-energy singlet and triplet states. Recent experiments have been directed at understanding how singlet and triplet nitrenium ions differ in their chemical reactivity. Singlet nitrenium ions typically react rapidly with nucleophiles whereas the triplet nitrenium ions tend to abstract H atoms. Several specific cases are discussed including the parent system, NH 2 , and several arylnitrenium ions.

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Section: Introductionmentioning

confidence: 99%

Singlet and triplet states in the reactions of nitrenium ions

Falvey

1999

J. Phys. Org. Chem.

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“…21 We observed that these two reagents gave outcomes similar than those obtained using BF 3 •OEt 2 within the limits of the different work-up required. Ratios of singlet N-substitution (a and b) vs triplet hydrogen-abstraction (c or other) products in protic TFSA/TFA are comparable with that previously reported for analogous dissociation of the phenyl azide in benzene.…”

Section: Methodsmentioning

confidence: 50%

BF3.OEt2-promoted synthesis of acridines via N-aryl nitrenium-BF3 ions generated by dissociation of 2-oxo azidoarenes in benzene

Fraleoni‐Morgera¹,

Zanirato²

2006

Arkivoc

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2-Oxo-substituted aryl azides such as 2-azidobenzenecarbaldehyde 1, 1-(2-azidophenyl)-1-ethanone 2 and (2-azidophenyl) (phenyl)methanone 3 react with benzene in the presence of BF 3 •OEt 2 , mainly affording 9-substituted acridines via formal 2-anilino-oxobenzene-BF 3 complexes rapidly followed by intramolecular cyclo-dehydration at the activated carbonyl groups. Under the same conditions, 2-azidobenzoic acid 4 gives mainly 2-anilinobenzoic acid 4b together with trace amounts of the 9(10H)-acridinone 4a. On the other hand, 2-azidobenzenecarbonitrile 5 gives the 9-amino acridine 5a via a conjugated imine, which undergoes intramolecular cyclization. The BF 3 •OEt 2 promoted dissociation of aryl azides to aryl nitrenium ions is compared with those promoted by AlCl 3 or a strong protic acid (TFA/TFSA mixture).

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“…[3,4] Recently, we tried to treat several aromatic compounds with N-arylhydroxylamine, including N-phenylhydroxylamine [4] and N- (4-tolyl)hydroxylamine (1), [5] in trifluoroacetic acid (TFA) in the presence of polyphosphoric acid (PPA) to produce the corresponding diarylamines by N-substitution as well as the corresponding aminobiphenyls by C-substitution. In these reactions, an arylnitrenium ion [6,7] should be a reactive intermediate with a canonical resonance form [8] wherein the positive charge populates carbon atoms of the ring and a nitrogen atom, and which then reacts with the aromatic compounds to give both the diarylamines and the aminobiphenyls. [3,4] 4-(Nitro and cyano)phenylnitrenium ions [2] from the corresponding aryl azides are efficiently capable of a selective aromatic N-substitution.…”

Section: Introductionmentioning

confidence: 99%