Thermal Intramolecular Transformation of Key Intermediates in the Photooxidation of para-Allyl-Substituted Phenyl Azide

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 117; no. 13; pp. 2728 - 2737
• Main Authors: Chainikova, Ekaterina M., Pankratyev, Evgeniy Yu, Teregulova, Aigul N., Gataullin, Rail R., Safiullin, Rustam L.
• Format: Journal Article
• Language: English; Russian
• Published: Washington, DC American Chemical Society 04.04.2013
• Subjects: Bonding; Electronic spectra; Isomers; Mathematical analysis; Nitriles; Oxides; Photooxidation; Transformations
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp401038g

The electronic spectra, kinetic regularities, and the mechanism of decay of the cis and trans isomeric forms of 4-[(2E)-1-methylbut-2-en-1-yl]phenylnitroso oxide (2) were studied by flash photolysis and product analysis. The mechanism of the consumption of this nitroso oxide is the same as the one proposed earlier for 4-methoxyphenylnitroso oxide. The trans-2 isomer is converted into cis-2, which undergoes cyclization to the substituted benzo[d][1,2,3]dioxazole 3. The reopening of the dioxazole ring yields nitrile oxide 4. The final product (3,4-dimethyl-3a,4-dihydro-2,1-benzisoxazol-5(3H)-ylidene)acetaldehyde (5) is formed by the intramolecular [3 + 2]-cycloaddition of the nitrile oxide group of 4 to the allylic double bond. To support the proposed mechanism, the quantum chemical calculations have been employed.