- Diindenopyrazines: Electron-Deficient Arenes
-
The syntheses, properties and application of the air-stable electron acceptors, diindenopyrazines 4 a–g are reported demonstrating the introduction of functional aryl groups in the 6- and 12-positions. The targets are accessible on the hundred milligram to gram scale. The structure of the aryl groups in 4 a–g modulates their solubility, redox potentials and optical properties. The introduction of electron-poor aryl groups to the electron-poor diindenopyrazine backbone reduces the electron affinity to ?4 eV, making the compounds attractive as n-semiconductors. A simple organic field-effect transistor of 4 e –without optimization– shows electron transport with a mobility of up to 0.037 cm2 V?1 s?1.
- Brosius, Victor,Bunz, Uwe H. F.,Freudenberg, Jan,Hippchen, Nikolai,Rominger, Frank,Weigold, Svenja
-
p. 10001 - 10005
(2021/06/07)
-
- Catalyst-Free Synthesis of Benzofuran Derivatives from Cascade Reactions between Nitroepoxides and Salicylaldehydes
-
Different benzofuran derivatives are synthesized via a catalyst-free reaction between nitroepoxides and salicylaldehydes. In the employed methodology, K2CO3 and DMF have been used at 110 °C, and the reactions were completed after 12 h in 33-84% yields. Th
- Ranjbari, Mohammad A.,Tavakol, Hossein
-
p. 4756 - 4762
(2021/04/02)
-
- Regioselective Opening of Nitroepoxides with Unsymmetrical Diamines
-
Nitroepoxides are easily transformed into benzodiazepines, tetrahydrobenzodiazepines, imidazopyridines, and N-alkyl tetrahydroquinoxalines by treatment with 2-aminobenzylamines, 2-aminopyridines, and N-alkyl 1,2-diaminobenzenes, respectively. Regioselectivity is controlled through attack of the most nucleophilic nitrogen of the unsymmetrical diamine to the β position of the epoxide. These reactions represent an efficient way to prepare privileged bioactive structures.
- Nosood, Yazdanbakhsh L.,Ziyaei Halimehjani, Azim,González, Florenci V.
-
p. 1252 - 1258
(2018/02/09)
-
- Preparation of Morpholines and Benzoxazines Starting from Nitroepoxides
-
Nitroepoxides are easily transformed into 2,3-disubstituted morpholines and 2,3-disubstituted benzoxazines in a two-step sequence by treatment with N-methylethanolamine and N-methyl-2-hydroxyaniline, respectively, in a highly stereoselective fashion.
- Capel,Vidal-Albalat,Rodríguez,González
-
p. 2572 - 2580
(2016/08/11)
-
- Catalytic enantioselective epoxidation of nitroalkenes
-
Nitroepoxides are potentially exploitable as synthons with vicinal electrophilic centers. Nevertheless, although advances have been made in the field, enantioselective epoxidation of nitroalkenes is still a challenging process. Herein we show a convenient procedure for the preparation of optically active nitroepoxides in high enantiomeric excess and high chemical yield. The kinetic data of the best catalyst have been examined using computational methods based on DFT calculations. Interestingly, the results demonstrate that the enantioselectivity of the epoxidation of nitroalkenes by this kind of catalyst is not only kinetically but also thermodynamically controlled.
- Vidal-Albalat,?widerek,Izquierdo,Rodríguez,Moliner,González
-
supporting information
p. 10060 - 10063
(2016/08/15)
-
- Catalytic enantioselective synthesis of α-nitroepoxides via aminolytic kinetic resolution
-
The first enantioselective synthesis of β-aryl-substituted α-nitroepoxides, exploiting an organocatalyzed aminolytic kinetic resolution (AKR), has been developed. Ring-opening reaction of racemic α-nitroepoxides with aniline in the presence of a readily available Cinchona alkaloid-derived thiourea affords unreacted epoxides in up to 95% ee.
- Meninno, Sara,Napolitano, Loris,Lattanzi, Alessandra
-
p. 124 - 128
(2015/02/02)
-
- Nitroepoxides as versatile precursors to 1,4-diamino heterocycles
-
Nitroepoxides are easily transformed into 1,4-diamino heterocycles such as quinoxalines and pyrazines by treatment with 1,2-benzenediamines and ammonia, respectively. Additionally, related saturated heterocycles, such as piperazines and tetrahydroquinoxalines, can be accessed by treatment with 1,2-diamines and a reducing agent. These transformations are efficient, provide access privileged, bioactive structures, and produce minimal waste.
- Vidal-Albalat, Andreu,Rodriguez, Santiago,Gonzalez, Florenci V.
-
supporting information
p. 1752 - 1755
(2014/04/17)
-
- α-nitro epoxides in organic synthesis: Development of a one-pot organocatalytic strategy for the synthesis of quinoxalines
-
A new strategy for the synthesis of biologically active quinoxalines by using versatile α-nitro epoxides as starting compounds has been developed. In addition, the in situ organocatalytic epoxidation of electron-poor nitro olefins followed by condensation with 1,2-phenylenediamines to provide quinoxalines in one pot has been demonstrated. The reaction of easily accessible nitro olefins with the tBuOOH/1,8-diazabicycloundec-7-ene (TBHP/DBU) organocatalytic system gives rise to the corresponding α-nitro epoxides, which are suitable for subsequent reaction with 1,2-phenylenediamines under mild conditions to give quinoxaline heterocycles in up to 82 % yield. Copyright
- Ibrahim, Mohammad M.,Grau, Dominik,Hampel, Frank,Tsogoeva, Svetlana B.
-
p. 1401 - 1405
(2014/03/21)
-
- α-Nitro Epoxides in Organic Synthesis: Development of a One-Pot Organocatalytic Strategy for the Synthesis of Quinoxalines
-
A new strategy for the synthesis of biologically active quinoxalines by using versatile α-nitro epoxides as starting compounds has been developed. In addition, the in situ organocatalytic epoxidation of electron-poor nitro olefins followed by condensation with 1,2-phenylenediamines to provide quinoxalines in one pot has been demonstrated.
- Ibrahim, Mohammad M.,Grau, Dominik,Hampel, Frank,Tsogoeva, Svetlana B.
-
p. 1401 - 1405
(2015/10/05)
-
- Dynamic kinetic asymmetric ring-opening/reductive amination sequence of racemic nitroepoxides with chiral amines: Enantioselective synthesis of chiral vicinal diamines
-
We report a highly diastereoselective synthesis of vicinal diamines by the treatment of nitroepoxides with primary amines and then a reducing agent. When using a chiral primary amine, racemic nitroepoxides are transformed into chiral diamines as a single enantiomers (>95:5 er) through a dynamic kinetic asymmetric transformation (DYKAT). The overall process is a one-pot procedure combining the exposure of nitroepoxides to chiral amines to afford diastereomeric mixtures of aminoimines and subsequent stereoselective imine reduction.
- Agut, Juan,Vidal, Andreu,Rodríguez, Santiago,González, Florenci V.
-
p. 5717 - 5722
(2013/07/25)
-
- Novel one-pot process for the synthesis of 1,3-thiazoles via organocatalysed epoxidation of nitro-olefins
-
A facile one-pot two-step process for the synthesis of 1,3-thiazole heterocycles via organocatalytic epoxidation of nitro-olefins with the t-BuOOH/DBU system, and subsequent reaction of α-nitro-epoxides with thioamides under mild conditions has been devel
- Weiss, Katharina M.,Wei, Shengwei,Tsogoeva, Svetlana B.
-
experimental part
p. 3457 - 3461
(2011/06/20)
-
- OXIDATIVE ADDITION OF HYDROXIDE ANIONS TO NITROALKENES VIA THE RADICAL ANIONS OF α-NITRO-OXIRANES
-
Stereoselective oxidative addition of hydroxide anions to nitroalkenes was carried out using potassium ferricyanide to yield α-nitro-oxiranes by a novel non-chain mechanism involving cyclisation of alkoxide anions onto α-nitroalkyl radicals.
- Bowman, W. Russel,Brown, David S.,Chaffin, Julie D. E.,Symons, Martyn C. R.,Jackson, Stuart W.,Willcocks, Neil A.
-
p. 2285 - 2288
(2007/10/02)
-
- A New Method for the Preparation of α-Nitroacetophenones
-
Treatment of readily available substituted β-nitrostyrenes with tert-butyl hydroperoxide and butyllithium gives synthetically useful α-nitroacetophenones in good yield.
- Ashwell, Mark A.,Jackson, Richard F. W.
-
p. 229 - 231
(2007/10/02)
-
- Fluoride-promoted Epoxidation of α,β-Unsaturated Compounds
-
The epoxidation of α,β-unsaturated compounds using tetrabutylammonium fluoride is described.This method has been demonstrated to be directly applicable to base-sensitive substrates such as cinnamaldehyde and α-phenylcinnamonitrile.
- Miyashita, Masaaki,Suzuki, Toshio,Yoshikoshi, Akira
-
p. 285 - 288
(2007/10/02)
-
- SYNTHETIC ENZYMES-4. HIGHLY ENANTIOSELECTIVE EPOXIDATION BY MEANS OF POLYAMINOACIDS IN A TRIPHASE SYSTEM: INFLUENCE OF STRUCTURAL VARIATIONS WITHIN THE CATALYSTS.
-
The asymmetric epoxidation of chalcone and other electron-poor olefins in a triphase system (water-organic solvent-polyaminoacid) affords optically active oxiranes.The influence of the molecular structure of catalysts and of their secondary conformation on the enantioselectivity of the reaction has also been examined.
- Colonna, Stefano,Molinari, Henriette,Banfi, Stefano,Julia, Sebastian,Masana, Jaume,Alvarez, Angel
-
p. 1635 - 1642
(2007/10/02)
-
- Synthetic Enzymes. Part 2. Catalytyc Asymmetric Epoxidation by means of Polyamino-acids in a Triphase System
-
The asymmetric epoxidation of several chalcones and other electron-poor olefins, in the presence of catalytic amounts of poly-(S)-amino-acids in a triphase system with optical yields of up to 96percent is described.The influence of the molecular structure of the catalysts and substrates, the solvent, and the temperature on the stereochemistry is discussed.
- Julia, Sebastian,Guixer, Joan,Masana, Jaume,Rocas, Jose
-
p. 1317 - 1324
(2007/10/02)
-