859966-58-8Relevant articles and documents
Electron-transfer-induced tautomerization in methylindanones: Electronic control of the tunneling rate for enolization
Bednarek,Zhu,Bally,Filipiak,Marcinek,Gebicki
, p. 2377 - 2387 (2007/10/03)
The radical cations generated from 4-methyl- and 4,7-dimethylindanone, as well as their deuterated isotopomers, isolated in Argon matrices, were found to undergo enolization to the corresponding enol radical cations at rates that differ by orders of magnitude. It is shown by quantum chemical calculations that the effect of the remote methyl group in the 4-position is of purely electronic nature in that it stabilizes the unreactive π-radical relative to the reactive σ-radical state of the 7-methylindanone radical cation. The observed kinetic behavior of the two compounds can be reproduced satisfactorily on the basis of calculated heigth and width of the thermal barrier for enolization, using the Bell model for quantum mechanical tunneling. High-level calculations on the methylacrolein radical cation show that barriers for enolization in radical cations are overestimated by B3LYP/6-31G*.
Modern Friedel-Crafts chemistry XIII. Intra- and intermolecular cyclization of some carbonyl derivatives under Friedel-Crafts conditions
Khalaf, Ali A.,Abdel-Wahab, Aboel-Magd A.,El-Khawaga, Ahmed M.,El-Zohry, Maher F.
, p. 285 - 291 (2007/10/02)
Carbonyl group deactivation in the cycloalkylation of aryl haloalkyl ketones was studied.Ketones 1-5 were prepared and subjected to treatment with AlCl3, AlCl3/H2SO4 and H2SO4 catalysts.Whereas AlCl3 catalyst gave no cyclization products, the use of AlCl3/H2SO4 and H2SO4 catalysts afforded the corresponding indanones and/or tetralones (6-11).The intermediate p-methylacrylophenone (12) was also obtained in the case of ketone 2.Furthermore intermolecular cyclizations of benzene, toluene and p-xylene with 3-chloropropionyl chloride (13) and 4-chlorobutyryl chloride (14) were investigated.In the presence of AlCl3/CH3NO2 catalyst, only the corresponding aryl haloalkyl ketones (1-5) were formed whereas the use of AlCl3 catalyst gave, in addition, some cyclic ketones.However, the use of AlCl3/H2SO4 catalyst gave only the corresponding cyclic ketones (6-11).Results are discussed and mechanisms are suggested.In conclusion, carbonyl group deactivation for ring closure is demonstrated in the investigated ketones and cyclization can only effected under strenuous conditions.
