7796-75-0Relevant academic research and scientific papers
Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3
Benaglia, Maurizio,Boselli, Monica Fiorenza,Faverio, Chiara,Gonzalez, Patricia Camarero,Puglisi, Alessandra
supporting information, p. 1041 - 1047 (2021/05/17)
Deep eutectic solvents (DESs) have gained attention as green and safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and β-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily reproducible protocol to isolate the product without the use of any organic solvent was established, and the recyclability of the DES mixture was successfully investigated.
A robust and stereocomplementary panel of ene-reductase variants for gram-scale asymmetric hydrogenation
Nett, Nathalie,Duewel, Sabine,Schmermund, Luca,Benary, Gerrit E.,Ranaghan, Kara,Mulholland, Adrian,Opperman, Diederik J.,Hoebenreich, Sabrina
, (2021/01/25)
We report an engineered panel of ene-reductases (ERs) from Thermus scotoductus SA-01 (TsER) that combines control over facial selectivity in the reduction of electron deficient C[dbnd]C double bonds with thermostability (up to 70 °C), organic solvent tolerance (up to 40 % v/v) and a broad substrate scope (23 compounds, three new to literature). Substrate acceptance and facial selectivity of 3-methylcyclohexenone was rationalized by crystallisation of TsER C25D/I67T and in silico docking. The TsER variant panel shows excellent enantiomeric excess (ee) and yields during bi-phasic preparative scale synthesis, with isolated yield of up to 93 % for 2R,5S-dihydrocarvone (3.6 g). Turnover frequencies (TOF) of approximately 40 000 h?1 were achieved, which are comparable to rates in hetero- and homogeneous metal catalysed hydrogenations. Preliminary batch reactions also demonstrated the reusability of the reaction system by consecutively removing the organic phase (n-pentane) for product removal and replacing with fresh substrate. Four consecutive batches yielded ca. 27 g L?1 R-levodione from a 45 mL aqueous reaction, containing less than 17 mg (10 μM) enzyme and the reaction only stopping because of acidification. The TsER variant panel provides a robust, highly active and stereocomplementary base for further exploitation as a tool in preparative organic synthesis.
Metal-Free Deoxygenation of Chiral Nitroalkanes: An Easy Entry to α-Substituted Enantiomerically Enriched Nitriles
Pirola, Margherita,Faverio, Chiara,Orlandi, Manuel,Benaglia, Maurizio
, p. 10247 - 10250 (2021/06/18)
A metal-free, mild and chemodivergent transformation involving nitroalkanes has been developed. Under optimized reaction conditions, in the presence of trichlorosilane and a tertiary amine, aliphatic nitroalkanes were selectively converted into amines or nitriles. Furthermore, when chiral β-substituted nitro compounds were reacted, the stereochemical integrity of the stereocenter was maintained and α-functionalized nitriles were obtained with no loss of enantiomeric excess. The methodology was successfully applied to the synthesis of chiral β-cyano esters, α-aryl alkylnitriles, and TBS-protected cyanohydrins, including direct precursors of four active pharmaceutical ingredients (ibuprofen, tembamide, aegeline and denopamine).
Radical Capture at Nickel(II) Complexes: C-C, C-N, and C-O Bond Formation
Bakhoda, Abolghasem Gus,Bertke, Jeffery A.,Figula, Bryan C.,Greene, Christine,Warren, Timothy H.,Wiese, Stefan
supporting information, p. 1710 - 1718 (2020/07/13)
The dinuclear β-diketiminato NiII tert-butoxide {[Me3NN]Ni}2(μ-OtBu)2 (2), synthesized from [Me3NN]Ni(2,4-lutidine) (1) and di-tert-butylperoxide, is a versatile precursor for the synthesis of a series of NiII complexes [Me3NN]Ni-FG (FG = functional group) to illustrate C-C, C-N, and C-O bond formation at NiII via radical capture. {[Me3NN]Ni}2(μ-OtBu)2 reacts with nitromethane, alkyl and aryl amines, acetophenone, benzamide, ammonia, and phenols to deliver the corresponding mono- or dinuclear [Me3NN]Ni-FG species (FG = O2NCH2, R-NH, ArNH, PhC(O)NH, PhC(O)CH2, NH2, and OAr). Many of these NiII complexes are capable of capturing the benzylic radical PhCH(?)CH3 to deliver the corresponding PhCH(FG)CH3 products featuring C-C, C-N, or C-O bonds. Density functional theory studies shed light on the mechanism of these transformations and suggest two competing pathways that depend on the nature of the functional groups. These radical capture reactions at [NiII]-FG complexes outline key C-C, C-N, and C-O bond forming steps, foreshadowing families of nickel radical relay catalysts.
Light-Enabled Enantiodivergence: Stereospecific Reduction of Activated Alkenes Using a Single Organocatalyst Enantiomer
Hostmann, Theresa,Molloy, John J.,Bussmann, Kathrin,Gilmour, Ryan
supporting information, p. 10164 - 10168 (2019/12/24)
Light-enabled enantiodivergence is demonstrated in which the alkene substrate configuration is manipulated (E → Z) prior to organocatalytic reduction with a chiral thiourea and Hantzsch ester. This allows stereodivergent reduction to be regulated at the substrate level with high fidelity and mitigates the need for a second, enantiomeric catalyst (up to 93:07 and 95:5 er). The synthetic utility of this strategy has been demonstrated in the synthesis of the weight-loss drug (R)-Lorcaserin (Belviq) and a potent AMPA modulator.
Autoinductive conversion of α,α-diiodonitroalkanes to amides and esters catalysed by iodine byproducts under O2
Li, Jing,Lear, Martin J.,Hayashi, Yujiro
supporting information, p. 6360 - 6363 (2018/06/21)
Studies to convert nitroalkanes into amides and esters using I2 and O2 revealed in situ-generated iodine species facilitate the homolytic C-I bond cleavage of α,α-diiodonitroalkanes, arguably in an autoinductive or autocatalytic manner. Consequently, we devised a rapid and economical I2/O2-based method to synthesise sterically hindered esters directly from primary nitroalkanes.
New insights into the catalytic reduction of aliphatic nitro compounds with hypophosphites under ultrasonic irradiation
Letort,Lejeune,Kardos,Métay,Popowycz,Lemaire,Draye
supporting information, p. 4583 - 4590 (2017/10/13)
This work describes an efficient process for the reduction of nitro compounds to the corresponding amines with a catalytic amount of Pd/C (0.6 mol%), and a mixture of sodium hypophosphite and hypophosphorous acid as a reducing agent in H2O/2-MeTHF at 60 °C. The reaction was optimized under silent conditions. The conditions for the in situ production of H2 using the mixture NaH2PO2/H3PO2 were studied. The influence of ultrasonic activation was investigated both in terms of efficiency and kinetics. The reaction was shown to be efficient in water, at 70 °C with a quantitative conversion and a maximal yield in only 15 min thanks to the ultrasonic activation. Finally, ultrasound was proved to act as a physical agent of phase transfer.
Enantioselective iridium-catalyzed hydrogenation of β,β-disubstituted nitroalkenes
Yu, Yan-Bo,Cheng, Lei,Li, Yi-Pan,Fu, Yue,Zhu, Shou-Fei,Zhou, Qi-Lin
supporting information, p. 4812 - 4815 (2016/04/09)
An iridium complex with a newly prepared chiral spiro amino-phosphine ligand efficiently catalyzed the hydrogenation of both β-aryl-β-methyl-nitroalkenes and β-alkyl-β-methyl-nitroalkenes to the corresponding saturated nitroalkanes, which represents the f
Metal-Templated Design: Enantioselective Hydrogen-Bond-Driven Catalysis Requiring only Parts-per-Million Catalyst Loading
Xu, Weici,Arieno, Marcus,L?w, Henrik,Huang, Kaifang,Xie, Xiulan,Cruchter, Thomas,Ma, Qiao,Xi, Jianwei,Huang, Biao,Wiest, Olaf,Gong, Lei,Meggers, Eric
supporting information, p. 8774 - 8780 (2016/08/02)
Based on a metal-templated approach using a rigid and globular structural scaffold in the form of a bis-cyclometalated octahedral iridium complex, an exceptionally active hydrogen-bond-mediated asymmetric catalyst was developed and its mode of action inve
Substrate Scope Evaluation of the Enantioselective Reduction of β-Alkyl-β-arylnitroalkenes by Old Yellow Enzymes 1-3 for Organic Synthesis Applications
Bertolotti, Mattia,Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Santangelo, Sara
, p. 577 - 583 (2016/02/23)
The substrate scope of the old yellow enzyme catalyzed reduction of β-alkyl-β-arylnitroalkenes is investigated. Compounds bearing either alkyl chains of increasing length at the carbon atom in position β to the nitro group or different substituents on the aromatic ring are prepared and submitted to bioreduction, to define the synthetic potential of this enantioselective reaction in the preparation of chiral fine chemicals. The versatility of the resulting nitroalkanes as chiral building blocks is shown by reducing the nitro group into a primary amine and by converting it into a carboxylic acid moiety by Meyer reaction. An "explosion" of chiral products can be observed by combining the highly enantioselective ene-reductase-mediated reduction of nitroalkenes with the chemical versatility of the nitro group.
