Ueber die Wanderung des Jodatomes in den Anisol‐ und Phenetol‐Derivaten

Reverdin, Frédéric

doi:10.1002/cber.18960290338

Cited by 16 publications

(2 citation statements)

References 2 publications

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“…The 2-halo-4-nitroanisole photoreactants were prepared from the available 2-haloanisoles by nitration in 1:1 HNO 3 (70%)/HOAc by the method of Reverdin . 2-Methoxy-5-nitrobenzonitrile was prepared similarly.…”

Section: Methodsmentioning

confidence: 99%

The Element Effect and Nucleophilicity in Nucleophilic Aromatic Photosubstitution (S_N2Ar*). Local Atom Effects as Mechanistic Probes of Very Fast Reactions

et al. 2008

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Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen ) F, Cl, Br, and I) with the nucleophiles hydroxide ion and pyridine have been investigated quantitatively to extend the findings recently communicated for cyanide ion. The halonitroanisoles on excitation form triplet π,π* states, which undergo substitution of the halogen by nucleophiles. Chemical yields of photoproducts, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields are reported for the five compounds with the three nucleophiles. Following a standard kinetic treatment, 73 rate constants are determined for elementary reactions of the triplets including quenching and various nucleophilic addition processes. The photoadditions are roughly 14 orders of magnitude faster than thermal counterparts. Rate constants for attack at the fluorine-bearing carbon of triplet 2-fluoro-4-nitroanisole are 2.9 × 10 9 , 1.3 × 10 9 , and 6.3 × 10 8 M -1 s -1 for cyanide ion, hydroxide ion, and pyridine, respectively. The relative rates for attack at the halogenbearing carbons for F/Cl/Br/I are 27:1.9:1.9:1 (cyanide ion), 29:2.6:2.4:1 (hydroxide ion), and 39:3.9: 3.5:1 (pyridine), respectively. The relative nucleophilicities vary somewhat with the attack site; they are about 5:2:1 for cyanide ion, hydroxide ion, and pyridine for attack at the halogen-bearing carbons. The trend of the element effect opposes that of aliphatic substitution and elimination but is similar in size and parallel to that of thermal nucleophilic aromatic substitution. Relative nucleophilicities in the photoreactions are also similar to those of comparable but vastly slower thermal reactions. The findings imply that the efficiency-determining step of the halogen photosubstitution is simple formation of a σ-complex through electron-paired bonding within the triplet manifold.

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Section: Methodsmentioning

confidence: 99%

The Element Effect and Nucleophilicity in Nucleophilic Aromatic Photosubstitution (S_N2Ar*). Local Atom Effects as Mechanistic Probes of Very Fast Reactions

et al. 2008

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“…Normal nitration ortho to the methoxy would produce 4-halo-2-nitroanisole, but ipso attack would lead to halogen migration and rearranged product, 2-halo-4-nitroanisole. I envisioned that this reaction would become known as the Perrin Rearrangement, but soon realized that I had been scooped by Frédéric Reverdin, who had discovered the Reverdin Rearrangement in 1896 …”

Section: Nitration Of Haloanisolesmentioning

confidence: 99%