5462-90-8Relevant academic research and scientific papers
Iridium-catalyzed highly chemoselective and efficient reduction of nitroalkenes to nitroalkanes in water
Chen, Yang,Liu, Changmeng,Xu, Dong,Xu, Jiaxi,Yang, Zhanhui
supporting information, p. 6050 - 6058 (2021/08/23)
An iridium-catalyzed highly chemoselective and efficient transfer hydrogenation reduction of structurally diverse nitroalkenes was realized at very low catalyst loading (S/C = up to 10000 or 20?000), using formic acid or sodium formate as a traceless hydride donor in water. Excellent functionality tolerance is also observed. The turnover number and turnover frequency of the catalyst reach as high as 18?600 and 19?200 h-1, respectively. An inert atmosphere protection is not required. The reactivities of nitroalkenes are dependent on their substitution pattern, and the pH value is a key factor to accomplish the complete conversion and excellent chemoselectivity. Purification of products is achieved by simple extraction without column chromatography. The reduction procedure is facilely amplified to 10 g scale at 10?000 S/C ratio. The potential of this green reduction in enantioselective hydrogenation has been demonstrated.
Organocatalytic enantioselective formal C(sp2)-H alkylation
Manna, Madhu Sudan,Mukherjee, Santanu
supporting information, p. 130 - 133 (2015/01/30)
An organocatalytic enantioselective formal C(sp2)-H alkylation is reported. This alkylative desymmetrization of prochiral 2,2-disubstituted cyclopentene-1,3-dione is catalyzed by a bifunctional tertiary aminourea derivative, utilizes air-stable and inexpensive nitroalkanes as the alkylating agents, and delivers synthetically versatile five-membered carbocycles containing an all-carbon quaternary stereogenic center remote from the reaction site in excellent enantioselectivity.
Useful extensions of the henry reaction: Expeditious routes to nitroalkanes and nitroalkenes in aqueous media
Chandrasekhar, Sosale,Shrinidhi, Annadka
, p. 3008 - 3018 (2014/10/16)
The products of the Henry nitroaldol reaction from nitromethane and several aldehydes were reduced to the corresponding nitroalkanes with (n-Bu) 3SnH in water under microwave irradiation (80 °C/10 min), or dehydrated to the corresponding nitroalkenes with K2CO3 in water (generally 0-5 °C/20 min). Both "one-pot" reactions occur in excellent yields across a range of aliphatic and aromatic (including heteroaromatic) substrates. It seems likely that the deoxygenation of the nitroaldols occurs via coordination of an oxygen atom of the nitro group with a tin atom, which facilitates hydride delivery in the transition state. The elimination of water from the nitroaldols in mild base is likely driven by the stability of the conjugated nitroalkene products. The elimination required workup with 2 N HCl, which likely displaces a nitroalkane-nitroalkene equilibrium towards the latter. These extensions of the Henry reaction lead to products not easily obtained otherwise.
Tuning the lewis acidity of boranes in frustrated lewis pair chemistry: Implications for the hydrogenation of electron-poor alkenes
Nicasio, Juan A.,Steinberg, Sebastian,Ines, Blanca,Alcarazo, Manuel
, p. 11016 - 11020 (2013/09/02)
An analysis of the metal-free reduction of electron deficient olefins by frustrated Lewis pairs indicates that the rate-determining step might be either the heterolytic cleavage of H2 to form an -onium borohydride salt, or the subsequent transfer of the hydride moiety to the substrate following a Michael-type addition reaction. While the use of strong Lewis acids such as B(C6F5)3 facilitates the first of these processes, hydride transfer to the olefin should be contrarily favoured by the use of weak Lewis acids which, for this very same reason, might be unable to promote the prior H2 split. After systematic testing of several boranes of different Lewis acidity (assessed by using the Childs' method) and steric demand, an optimal situation that employs tris(2,4,6-trifluorophenyl) borane was reached. Mixtures of this borane with 1,4-diazabicyclo[2.2.2]octane (DABCO) exhibited excellent catalytic activity for the hydrogenation of alkylidene malonates. In fact, this transformation could be achieved under milder conditions than those we reported previously. Moreover, the reaction scope could be expanded to other electron deficient olefins containing esters, sulfones or nitro functionalities as electron-withdrawing substituents.
Functional-group tolerance in frustrated lewis pairs: hydrogenation of nitroolefins and acrylates
Greb, Lutz,Daniliuc, Constantin-Gabriel,Bergander, Klaus,Paradies, Jan
supporting information, p. 5876 - 5879 (2013/07/05)
Weak Lewis acid for high nucleophilicity: Hydridoborate derived from B(2,6-F2C6H3)3 shows significant hydride character. Solid-state and solution structure analysis revealed a dihydrogen-bonded aggregate. The new frustrated Lewis pair was applied in the hydrogenation of nitroolefins and acrylates (see scheme; EWG=electron- withdrawing group). The decreased Lewis acidity provides higher reactivity and functional-group tolerance. Copyright
New approach to oximes through reduction of nitro compounds enabled by visible light photoredox catalysis
Cai, Shunyou,Zhang, Shaolong,Zhao, Yaohong,Wang, David Zhigang
supporting information, p. 2660 - 2663 (2013/07/11)
A range of nitro compounds are smoothly reduced to their corresponding oximes under the synergistic effects of visible light irradiation, the Ru(bpy)3Cl2 photocatalyst, Hünig's base, Mg(ClO 4)2 activation, and MeCN solvent. This remarkably mild and environmentally benign protocol, when orchestrated with classical Beckmann rearrangement, enables such high-value industrial feedstock as caprolactam to be readily accessed from simple precursor nitrocyclohexane.
S-benzyl isothiouronium chloride as a recoverable organocatalyst for the reduction of conjugated nitroalkenes with Hantzsch ester
Nguyen, Quynh Pham Bao,Kim, Jae Nyoung,Kim, Taek Hyeon
supporting information; experimental part, p. 6513 - 6516 (2012/08/28)
The reduction of conjugated nitroalkenes into nitroalkanes with Hantzsch ester using S-benzyl isothiouronium chloride as a recoverable organocatalyst was successfully accomplished with high yield and excellent chemoselectivity.
Visible-light-promoted C-C bond cleavage: Photocatalytic generation of iminium ions and amino radicals
Cai, Shunyou,Zhao, Xinyang,Wang, Xinbo,Liu, Qisong,Li, Zigang,Wang, David Zhigang
supporting information; experimental part, p. 8050 - 8053 (2012/08/29)
Photoscissors: Structurally variable and synthetically robust iminium ions and amino radicals species could be simultaneously generated by visible-light-promoted photoredox cleavage of the C-C bonds in simple vicinal diamine precursors under very mild reaction conditions. Copyright
Catalyst-free and solventless Hantzsch ester mediated reduction of nitroolefins at elevated temperature
Chauhan, Pankaj,Kaur, Kirandeep,Bala, Neeraj,Kumar, Vikas,Chimni, Swapandeep Singh
experimental part, p. 304 - 309 (2011/05/02)
A catalyst-free and solventless protocol for the reduction of nitroolefins to the corresponding nitroalkanes at 100°C has been developed. Various nitroalkenes have been reduced in good to excellent yield with short reaction times.
Characterization of xenobiotic reductase A (XenA): Study of active site residues, substrate spectrum and stability
Yanto, Yanto,Yu, Hua-Hsiang,Hall, Melanie,Bommarius, Andreas S.
supporting information; scheme or table, p. 8809 - 8811 (2011/02/28)
Xenobiotic reductase A (XenA) has broad catalytic activity and reduces various α,β-unsaturated and nitro compounds with moderate to excellent stereoselectivity. Single mutants C25G and C25V are able to reduce nitrobenzene, a non-active substrate for the wild type, to produce aniline. Total turnover is dominated by chemical rather than thermal instability. The Royal Society of Chemistry 2010.
