- NaH-mediated direct C-H arylation in the presence of 1,10-phenanthroline
-
Transition-metal-free coupling of haloarenes with unactivated arenes has been developed in the presence of NaH and 1,10-phenanthroline. Various haloarenes bearing methyl, methoxy, halogen (fluoride, chloride, and bromide), cyano, trifluoromethyl, ester, and amide groups can be cross-coupled with unactivated arenes, or heteroarenes in this reaction.
- Nozawa-Kumada, Kanako,Iwakawa, Yuki,Onuma, So,Shigeno, Masanori,Kondo, Yoshinori
-
supporting information
p. 7773 - 7776
(2020/07/27)
-
- Direct C-H photoarylation of diazines using aryldiazonium salts and visible-light
-
In this study, direct C-H photoarylation of pyrazine with aryldiazonium salts under visible-light irradiation (blue-LEDs) is described, and additional examples including photoarylations of pyrimidine and pyridazine are also covered. The corresponding aryl-diazines were prepared in yields up to 84% only by mixing and irradiating the reaction with no need for an additional photocatalyst. We demonstrate the efficacy of this protocol by the scope with electron-donor, -neutral, and -withdrawing groups attached at the ortho, meta, and para positions of the aryldiazonium salts; the results are better than those reported for ruthenium-complex mediated photoarylations. Additionally, we demonstrate the robustness of this methodology with a 5 mmol scaled-up experiment. Mechanistic studies were carried out giving support to the proposal of a photocatalyzed approach by an electron donor-acceptor (EDA) complex, also highlighting the crucial role that solvents play in the formation of the EDA complex. This journal is
- Silva, Rodrigo C.,Villela, Lucas F.,Brocksom, Timothy J.,De Oliveira, Kleber T.
-
p. 31115 - 31122
(2020/09/23)
-
- Graphene oxide-phenalenyl composite: transition metal-free recyclable and catalytic C-H functionalization
-
An efficient route towards a heterogeneous transition metal-free catalytic C-H functionalization using a covalently linked graphene oxide-phenalenyl conjugate is described herein (28 examples, which include a core of some biologically relevant biaryl and hetero-biaryls). It is an environmentally benign, economical and heterogeneous platform, whose catalytic activity can easily be regenerated through a simple washing-drying technique and the catalytic activity can be retained even after 10 cycles.
- Singh, Bhagat,Paira, Rupankar,Biswas, Goutam,Shaw, Bikash Kumar,Mandal, Swadhin K.
-
supporting information
p. 13220 - 13223
(2018/12/10)
-
- Synthesis of Chiral Piperazines via Hydrogenation of Pyrazines Activated by Alkyl Halides
-
A facile method has been developed for the synthesis of chiral piperazines through Ir-catalyzed hydrogenation of pyrazines activated by alkyl halides, giving a wide range of chiral piperazines including 3-substituted as well as 2,3- and 3,5-disubstituted
- Huang, Wen-Xue,Liu, Lian-Jin,Wu, Bo,Feng, Guang-Shou,Wang, Baomin,Zhou, Yong-Gui
-
supporting information
p. 3082 - 3085
(2016/07/13)
-
- Iodine-mediated oxidative annulation for one-pot synthesis of pyrazines and quinoxalines using a multipathway coupled domino strategy
-
An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.
- Viswanadham, K. K. Durga Rao,Prathap Reddy, Muktapuram,Sathyanarayana, Pochampalli,Ravi, Owk,Kant, Ruchir,Bathula, Surendar Reddy
-
supporting information
p. 13517 - 13520
(2015/01/09)
-
- Iron-catalyzed cross-coupling of electron-deficient heterocycles and quinone with organoboron species via innate C-H functionalization: Application in total synthesis of pyrazine alkaloid botryllazine A
-
Here, we report an iron-catalyzed cross-coupling reaction of electron-deficient heterocycles and quinone with organoboron species via innate C-H functionalization. Iron(II) acetylacetonate along with oxidant (K 2S2O8) and phase-transfer catalyst (TBAB) under open flask conditions efficiently catalyzed the cross-coupling of pyrazine with arylboronic acids and gave monoarylated products in good to excellent yields. Optimized conditions also worked for other heterocylces such as quinoxalines, pyridines, quinoline, and isoquinoline as well as quinones. In addition, we demonstrated as a first example its application for the synthesis of anticancer marine pyrazine alkaloid botryllazine A.
- Singh, Parvinder Pal,Aithagani, Sravan Kumar,Yadav, Mahipal,Singh, Varun Pratap,Vishwakarma, Ram A.
-
p. 2639 - 2648
(2013/04/24)
-
- Potassium t-butoxide alone can promote the biaryl coupling of electron-deficient nitrogen heterocycles and haloarenes
-
(Chemical Equation Presented) The biaryl coupling of electron-deficient nitrogen heterocycles and haloarenes can be promoted by potassium t-butoxide alone, without the addition of any exogenous transition metal species. Electron-deficient nitrogen heterocycles such as pyridine, pyridazine, pyrimidine, pyrazine, and quinoxaline are arylated with haloarenes. Control experiments support a radical-based mechanism. Taking these findings into account, radical processes may be partially involved in the reported transition-metal-catalyzed arylation reactions employing t-butoxide bases and haloarenes under elevated temperatures or under microwave irradiation.
- Yanagisawa, Shuichi,Ueda, Kirika,Taniguchi, Tadashi,Itami, Kenichiro
-
supporting information; scheme or table
p. 4673 - 4676
(2009/05/13)
-