Smiles rearrangement photo

Excited-state intramolecular nucleophilic aromatic substitutions are known as photo-Smiles rearrangements. Ealier, these were reported for 2,4-dinitrophenyl ethers and. v-lriazinyl ethers32. The exploratory33 and mechanistic34 studies on photo-Smiles rearrangements of p-(nitrophenoxy)- >-anilinoalkanes were carried out (equation 28). 

As depicted in Scheme 53 the photo-Smiles rearrangement involves radical ion pairs. Intermediately the spiro-type Meisenheimer complex 277 is formed... 

The photoaddition to aromatic ring is simply classified in Table 13. Direct attack of nucleophiles such as cyanide anion and carbanion to aromatic rings in the excited species has been recognized by SRN2 reactions [Eq. (4)], which were discussed in the past three decades [27,28], We will discuss briefly some examples in this section, including intramolecular photocyclization such as photo-Smiles rearrangement. 

Matsui, K., Maeno, N., Suzuki, S., Shizuka, H., Morita, T. Photo-Smiles rearrangements. Tetrahedron Lett. 1970, 1467-1469. 

Photoamination of arenes the nucleophilic photosubstitution SN2Ar was briefly discussed in Section 6.2.3. An intramolecular version of such a reaction, termed photo-Smiles rearrangement, is shown in Scheme 6.199.1226... 

Wubbels, G. G., Sevetson, B. R., Sanders, H., Competitive Catalysis and Quenching by Amines of Photo Smiles Rearrangement as Evidence for a Zwitterionic Triplet as the Proton donating Intermediate, J. Am. Chem. Soc. 1989, 111, 1018 1022. 

The a-CD complexation proved to be effective in modifying the course of the photo-Smiles rearrangement of p-nitrophenyl ethers 100 (Scheme 18). The reaction mechanism in solution involves a heterolytic nucleophilic attack on the triplet state to give the high-energy zwitterionic final product either directly or by irreversibly losing a proton (base-catalyzed reaction). In the base-catalyzed... 

Intramolecular nucleophilic photosubshtutions have also been reported. The most commonly found example is the photo-Smiles rearrangement, which is the conversion of aryl-co-aminoalkylethers into the corresponding substituted anilines upon irradiahon [10, 97, 98]. Recently, the photochemistry of (Z)-N-acyldehy-droarylalaninamides in methanol in the presence of a base, such as DBU or triethylamine (TEA), has been reported and found to produce substituted dihydroquinolinones in high yields (Scheme 14.20) [99-101]. The reaction is initiated by ET from the amine to the excited state of the amide. Competitive side reactions were also observed, thereby lowering the yields of the cyclized products. 

New syntheses of cyclic tertiary amines from iV-chloramines, allylic tertiary amines from Pd(0) complexes, 2,6-disubstituted anilines from enamines, and 2-arylaminoalcohols via a photo-Smiles rearrangement have been published. 

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