Reactions of aN-Acyliminium Ion Pool with Benzylsilanes. Implication of a Radical/Cation/Radical Cation Chain Mechanism Involving Oxidative C−Si Bond Cleavage

2007 ◽  
Vol 129 (7) ◽  
pp. 1902-1903 ◽  
Author(s):  
Tomokazu Maruyama ◽  
Yusuke Mizuno ◽  
Ikuo Shimizu ◽  
Seiji Suga ◽  
Jun-ichi Yoshida
ChemInform ◽  
2007 ◽  
Vol 38 (24) ◽  
Author(s):  
Tomokazu Maruyama ◽  
Yusuke Mizuno ◽  
Ikuo Shimizu ◽  
Seiji Suga ◽  
Jun-ichi Yoshida

1991 ◽  
Vol 69 (5) ◽  
pp. 839-852 ◽  
Author(s):  
Donald R. Arnold ◽  
Xinyao Du ◽  
Kerstin M. Henseleit

The effect of meta- and para-methoxy substitution on the reactivity of some radical cations has been determined. The compounds chosen for study were 1-(3-methoxyphenyl)-1-phenylethylene (7), 1-(4-methoxyphenyl)-1-phenylethylene (8), 3-(3-methoxyphenyl)indene (9), 3-(4-methoxyphenyl)indene (10), methyl 2-(3-methoxyphenyl)-2-phenylethyl ether (11), methyl 2-(4-methoxyphenyl)-2-phenylethyl ether (12), cis- and trans-2-methoxy-1-(3-methoxyphenyl)indane (13), and cis- and trans-2-methoxy-1-(4-methoxyphenyl)indane (14). The radical cations of these compounds were generated by photosensitization (electron transfer) using 1,4-dicyanobenzene (3) as the electron acceptor. The three reactions studied were: (1) The addition of nucleophiles (methanol) to the radical cation of the arylalkenes, a reaction that yields the anti-Markovnikov addition product. (2) The carbon–carbon bond cleavage of radical cations, which yields products derived from the radical and carbocation fragments. (3) The deprotonation of the radical cation, a reaction that can be used to invert the configuration at a saturated carbon centre. The mechanisms of these reactions are discussed and the factors that need to be considered in order to predict reactivity are defined. Molecular orbital calculations (UHF/STO-3G) were carried out on the radical cations of the model compounds 3- and 4-vinylanisole and 3- and 4-methylanisole. Key words: photochemistry, photosensitize (electron transfer), radical cation, radical.


1970 ◽  
Vol 48 (4) ◽  
pp. 544-545 ◽  
Author(s):  
F. Minisci ◽  
G. P. Gardini ◽  
F. Bertini

The metal ion catalyzed chlorination of 1-chlorobutane, 1-chlorohexane, methyl-pentanoate, and methyl-heptanoate by protonated N-chloroamines proceeds by a free radical chain mechanism and the chain carrying species was shown not to be a chlorine atom, but an amino radical cation.


2004 ◽  
Vol 116 (14) ◽  
pp. 1904-1907
Author(s):  
Daniele Catone ◽  
Anna Giardini Guidoni ◽  
Alessandra Paladini ◽  
Susanna Piccirillo ◽  
Flaminia Rondino ◽  
...  

1991 ◽  
Vol 69 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Donald R. Arnold ◽  
Laurie J. Lamont ◽  
Allyson L. Perrott

The reactivity of the radical cations of methyl 2,2-diphenylcyclohexyl ether (7), 6,6-diphenyl-1,4-dioxaspiro[4.5]decane (8), methyl cis- and trans-2-phenylcyclohexyl ether (9cis and trans), and 6-phenyl-1,4-dioxaspiro[4.5]decane (10), generated by photosensitized (electron transfer) irradiation, has been studied. Solutions of the ethers and acetals in acetonitrile–methanol (3:1), with 1,4-dicyanobenzene (2) serving as the electron acceptor, were irradiated with a medium-pressure mercury vapour lamp through Pyrex. The diphenyl derivatives 7 and 8 were reactive; 7 gave 6,6-diphenylhexanal dimethyl acetal (11) and 8 gave 2-methoxy-2-(5,5-diphenylpentyl)-1,3-dioxolane (12). These are the products expected from the intermediate 1,6-radical cation, formed upon carbon–carbon bond cleavage of the cyclic radical cation. The monophenyl derivatives 9cis and trans and 10 were stable under these irradiation conditions. The mechanism for the carbon–carbon bond cleavage and for the cis–trans isomerization is discussed. An explanation, based upon conformation, is offered for the lack of reactivity of 9 and 10. Molecular mechanics (MM2) calculations were used to determine the preferred conformation of 9cis and trans, and 10. Key words: photosensitization, electron transfer, radical cation, carbon–carbon bond cleavage, conformation.


2003 ◽  
Vol 68 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Devarajan Ajitha ◽  
Kimihiko Hirao ◽  
Sourav Pal

Using the Fock space multireference coupled-cluster (FS-MRCC) analytical linear response approach, we report the dipole moments of low-lying singlet and triplet excited states of ozone. The low-lying singlet and triplet excited states are calculated at the ground-state geometry and at the adiabatic geometry for the 1A2 and 1B1. For comparison we also calculate at the ground-state geometry the dipole moments of the 1A2, 1B1 and 1B2 using multireference configuration interaction (MRCI) with a bigger VQZ basis and complete active space. We also report as by-product the excitation energy values in the singles and doubles approximation. At the ground-state geometry we also report the energy and the dipole moments of the 2A1, 2A2 and 2B1 states of the ozone radical cation. The energy of the ozone cation radical is compared with the other correlated approaches. It matches well with the experimental values.


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