1176891-87-4Relevant academic research and scientific papers
Oxidative C - C bond formation (Scholl Reaction) with DDQ as an efficient and easily recyclable oxidant
Zhai, Linyi,Shukla, Ruchi,Rathore, Rajendra
, p. 3474 - 3477 (2009)
DDQ in the presence of an acid is known to oxidize a variety of aromatic donors to the corresponding cation radicals. Herein, we now demonstrate that the DDQ/H+ system can be effectively utilized for the oxidative C - C bond formations or biaryl synthesis. The efficient preparation of a variety of polyaromatic hydrocarbons including graphitic hexa-peri-hexabenzocoronenes, ease of isolation of the clean products, and ready regeneration of DDQ from easily recovered reduced DDQ-H2 advances the use of DDQ/H+ for Scholl reactions.
An economical and environmentally friendly oxidative biaryl coupling promoted by activated MnO2
Yang, Jingjing,Sun, Shutao,Zeng, Ziyu,Zheng, Hongbo,Li, Wei,Lou, Hongxiang,Liu, Lei
, p. 7774 - 7779 (2014)
An activated manganese dioxide (MnO2)-BF3·OEt2 oxidation system was developed to efficiently mediate the intramolecular as well as intermolecular biaryl coupling. The oxidative coupling proceeds smoothly at ambient temperature to deliver the corresponding five- to eight-membered tricyclic products in good to excellent yields. The employment of the combination of MnO2 and BF3·OEt2 is attractive on the basis of economical and environmental issues.
Dihedral-Angle-Controlled Crossover from Static Hole Delocalization to Dynamic Hopping in Biaryl Cation Radicals
Talipov, Marat R.,Navale, Tushar S.,Hossain, Mohammad M.,Shukla, Ruchi,Ivanov, Maxim V.,Rathore, Rajendra
supporting information, p. 266 - 269 (2016/12/30)
In cases of coherent charge-transfer mechanism in biaryl compounds the rates follow a squared cosine trend with varying dihedral angle. Herein we demonstrate using a series of biaryl cation radicals with varying dihedral angles that the hole stabilization
Modular access to 9,9-spirobifluorenes by oxidative coupling using molybdenum pentachloride
Trosien, Simon,Schollmeyer, Dieter,Waldvogel, Siegfried R.
supporting information, p. 1160 - 1164 (2013/06/04)
The strong oxidizing agent molybdenum pentachloride was used for an efficient direct C-C bond formation of 9,9-diarylfluorenes to the corresponding 9,9-spirobifluorenes. Thus, a versatile method that is compatible with labile groups, such as iodo moieties
Probing the arenium-ion (ProtonTransfer) versus the cation-radical (Electron Transfer) mechanism of scholl reaction using DDQ as oxidant
Zhai, Linyi,Shukla, Ruchi,Wadumethrige, Shriya H.,Rathore, Rajendra
supporting information; experimental part, p. 4748 - 4760 (2010/09/05)
(Figure Presented) DDQ/H+ system readily oxidizes a variety of electron donors with oxidation potential as high as ～1.7 V to the corresponding cation radicals. A re-examination of the controversial arenium-ion versus cation-radical mechanisms for Scholl reaction using DDQ/H+ together with commonly utilized FeCl3 as oxidants led us to demonstrate that the reaction proceeds largely via a cation-radical mechanism. The critical experimental evidence in support of a cation-radical pathway for the Scholl reaction includes the following: (i) There is no reaction in Scholl precursors in a mixture of dichloromethane and various acids (10% v/v). (ii) The necessity to use powerful oxidants such as ferric chloride (FeCl3) or DDQ/H+ for Scholl reactions is inconsistent with the arenium-ion mechanism in light of the fact that aromatization of the dihydro intermediates (formed via arenium-ion mechanism) can be easily accomplished with rather weak oxidants such as iodine or air. (iii) Various Scholl precursors with oxidation potentials 1.7 V vs SCE undergo ready oxidative C-C bond formation with DDQ/H+ as oxidant, whereas Scholl precursors with oxidation potentials greater than >1.7 V vs SCE do not react. (iv) Finally, the feasibility of the dicationic intermediate, formed by loss of two electrons, has been demonstrated by its generation from a tetraphenylene derivative using DDQ/H+ as an oxidant.
