Competitive reactivity of nitrenium and carbenium ion contributors of purinium cations with "soft" bases

Parham, James C.; Templeton, Mary Agnes

doi:10.1021/jo00343a010

Cited by 11 publications

(3 citation statements)

References 10 publications

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“…Parham and Templeton examined the regiochemistry of nucleophilic addition to purinium cations and rationalized their results in terms of a frontier molecular orbital (FMO) analysis . Extension of this analysis to simple arylnitrenium ions leads to the following predictions.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Diarylnitrenium Ions with Electron Rich Alkenes: An Experimental and Theoretical Study

1997

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Photolysis of N-(diphenylamino)-2,4,6-trimethylpyridinium tetrafluoroborate (1a) and N-[bis(4-methylphenyl)amino]-2,4,6-trimethylpyridinium salt (1b) gives products attributable to diarylnitrenium ion (Ar(2)N(+), 2). The major products of these reactions include products from nucleophilic addition of various pi-nucleophiles (e.g. electron rich alkenes) to the ortho and para positions of one of the phenyl rings. Nanosecond and EPR spectroscopy show that radicals also form. These radicals are thought to give rise to the diarylamines isolated as minor products from the photolysis of 1aand 1b. In addition to the para addition products and Ph(2)NH, N-phenylindoles and N-phenylindolinones are isolated when silyl enol ethers and silyl ketene acetals are used as trapping agents, respectively. The indoles and indolinones are generated from initial addition of the nucleophile to the ortho position on 2 followed by cyclization of the resulting intermediate. A product resulting from N addition of the nucleophile to 2 is isolated only when silyl ketene acetals are used. A number of electronic sturcture calculations at different levels of molecular orbital and density functional theory were carried out on Ph(2)N(+). There do not seem to be effects associated with either the charge distribution or the LUMO that would strongly influence ortho/para/N selectivity in nucleophilic trapping. Laser flash photolysis on 1a provides absolute rate constants for the nucleophilic addition of various alkenes to Ph(2)N(+). These fall in the range of 10(9)-10(10) M(-)(1) s(-)(1) and correlate with the oxidation potential of the alkene. From these data it is clear that the more easily oxidized the alkene the faster it will react with Ph(2)N(+).

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Section: Introductionmentioning

confidence: 99%

Reactions of Diarylnitrenium Ions with Electron Rich Alkenes: An Experimental and Theoretical Study

1997

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“…As a continuation of our research interest toward controlling the reactivity of nonprefunctionalized aromatic systems by weak interactions, an unprecedented, N -selective arylation of sulfonanilides via the regulation of the reactivity of a nitrenium ion over a carbenium ion by soft–hard acid–base (SHAB) control is reported . Nitrenium ions are well-known soft electrophiles, whereas carbenium ions can be hard electrophiles because when they are formed from the corresponding nitrenium ion the ring current is broken (Scheme a). Additionally, due to electron delocalization, the biphenyls or 1,2-diphenyl acetylenes are expected to act as soft nucleophiles.…”

Section: Results and Discussionmentioning

confidence: 99%

Soft–Hard Acid/Base-Controlled, Oxidative, N-Selective Arylation of Sulfonanilides via a Nitrenium Ion

Maiti

Mal

2018

J. Org. Chem.

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In iodine(III)-catalyzed, dehydrogenative arylations of sulfonanilides, the functionalization of C-C bonds is preferred over the functionalization of C-N bonds. Herein, an unprecedented N-selective arylation of sulfonanilides using soft-hard acid-base (SHAB) control by a nitrenium ion over a carbenium ion is reported. Treatment of sulfonanilides with iodine(III) led to the formation of nitrenium ions (soft), which preferentially react with biphenyls (soft) over bimesityl (hard) to generate C-N bonds. The iodine(III) was generated in situ by using PhI and mCPBA at room temperature.

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“…As shown in Scheme , the softer electrophile nitrenium ion is switchable to the harder electrophile carbenium ion by losing the aromatic ring current . Kikugawa and co‐workers have shown that by‐product iodobenzene from the reactions of anilides and phenyliodinetrifluoroacetate (PIFA) reacted further for a dehydrogenative C−N bond formation reaction .…”

Section: Figurementioning

confidence: 99%

Soft–Hard Acid–Base‐Controlled C−H Trifluoroethoxylation and Trideuteriomethoxylation of Anilides

2018

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Phenyliodinetrifluoroacetate (PIFA)-mediated dehydrogenative CÀHe therification of anilides is reported for the synthesis of -OCH 2 CF 3 and -OCD 3 incorporated aryl ethers. Nucleophilicity of the added nucleophiles and soft-hard acid-base (SHAB) principle were rationalized to understandt hose reactions. Anilides and PIFAl ed to the electrophiles either softer nitrenium ions or harder carbenium ions. The harder nucleophile alcohols exclusively reacted with the carbenium ions to produce aryl ethers.

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Competitive reactivity of nitrenium and carbenium ion contributors of purinium cations with "soft" bases

Cited by 11 publications

References 10 publications

Reactions of Diarylnitrenium Ions with Electron Rich Alkenes: An Experimental and Theoretical Study

Reactions of Diarylnitrenium Ions with Electron Rich Alkenes: An Experimental and Theoretical Study

Soft–Hard Acid/Base-Controlled, Oxidative, N-Selective Arylation of Sulfonanilides via a Nitrenium Ion

Soft–Hard Acid–Base‐Controlled C−H Trifluoroethoxylation and Trideuteriomethoxylation of Anilides

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