scholarly journals Electron-Transfer-Induced Intermolecular [2 + 2] Cycloaddition Reactions Assisted by Aromatic “Redox Tag”

10.5772/33707 ◽  
2012 ◽  
Author(s):  
Kazuhiro Chiba ◽  
Yohei Ok
Keyword(s):  
Electron Transfer ◽  
Cycloaddition Reactions

Electron-Transfer-Induced Intermolecular [2 + 2] Cycloaddition Reactions Based on the Aromatic “Redox Tag” Strategy

2011 ◽  
Vol 76 (9) ◽  
pp. 3470-3476 ◽  
Author(s):  
Yohei Okada ◽  
Asaki Nishimoto ◽  
Ryoichi Akaba ◽  
Kazuhiro Chiba
Keyword(s):  
Electron Transfer ◽  
Cycloaddition Reactions

Study of trichloronitrosomethane: regioselective cycloadditions of 2-substituted-1,3-butadienes

1989 ◽  
Vol 67 (12) ◽  
pp. 2153-2161 ◽  
Author(s):  
Cheng-Tung Lin ◽  
Wen-Jei Hsu
Keyword(s):  
Electron Transfer ◽  
Reaction Mechanism ◽  
Transition State ◽  
Molecular Orbital ◽  
Kinetic Studies ◽  
Frontier Molecular Orbital ◽  
Cycloaddition Reactions ◽  
Orientation Preference ◽  
Straight Lines ◽  
Concerted Reaction

The regioselectivity of cycloaddition reactions of trichloronitrosomethane (1) with 2-alkyl (R = Me, Et, i-Pr, t-Bu, CF3, Bz, and Cl) and 2-aryl (Ar = Ph, 4-CH3OPh, 4-CH3Ph, 3-CH3Ph, and 4-ClPh) 1,3-butadienes is described. The orientation of cycloaddition is substituent dependent, producing 2,5-disubstituted (para) and 2,4-disubstituted (meta) 3,6-dihydro-1,2-oxazines from 2-alkyl- and 2-aryl-1,3-butadienes respectively. Increasing the bulk of the substituent from methyl to tert-butyl in 2-alkyl-1,3-butadienes increases the regioselectivity. Kinetic studies in various solvents indicate that plots of log km/kH vs. Hammett σ+ values give straight lines with the ρ values lying between −0.60 and −0.91 for the reactions with 2-aryl-1,3-butadienes. A concerted reaction mechanism is proposed and the orientation preference is consistent with frontier molecular orbital predictions for 2-alkyl-1,3-butadienes. In the reactions with 2-aryl-1,3-butadienes, a transition state leading to a spin-paired diradical, which then converts by partial electron transfer to zwitterionic structure, is proposed. Keywords: trichloronitrosomethane, 3,6-dihydro-1,2-oxazine, regioselectivity, [2 + 4] cycloaddition.

scholarly journals Radical Cation Cycloaddition Reactions of 2-Vinylbenzofurans and 2-Vinylfurans by Photoinduced Electron Transfer.

1998 ◽  
Vol 52 ◽  
pp. 175-193 ◽  
Author(s):  
Jörg Botzem ◽  
Udo Haberl ◽  
Eberhard Steckhan ◽  
Siegfried Blechert ◽  
Inger Søtofte ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Photoinduced Electron Transfer ◽  
Cycloaddition Reactions
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