3156-72-7Relevant academic research and scientific papers
Enantiocomplementary Michael Additions of Acetaldehyde to Aliphatic Nitroalkenes Catalyzed by Proline-Based Carboligases
Kunzendorf, Andreas,Poelarends, Gerrit J.,Saifuddin, Mohammad
, (2022/02/09)
The blockbuster drug Pregabalin is widely prescribed for the treatment of painful diabetic neuropathy. Given the continuous epidemic growth of diabetes, the development of sustainable synthesis routes for Pregabalin and structurally related pharmaceutically active γ-aminobutyric acid (GABA) derivatives is of high interest. Enantioenriched γ-nitroaldehydes are versatile synthons for the production of GABA derivatives, which can be prepared through a Michael-type addition of acetaldehyde to α,β-unsaturated nitroalkenes. Here we report that tailored variants of the promiscuous enzyme 4-oxalocrotonate tautomerase (4-OT) can accept diverse aliphatic α,β-unsaturated nitroalkenes as substrates for acetaldehyde addition. Highly enantioenriched aliphatic (R)- and (S)-γ-nitroaldehydes were obtained in good yields using two enantiocomplementary 4-OT variants. Our results underscore the synthetic potential of 4-OT for the preparation of structurally diverse synthons for bioactive analogues of Pregabalin.
Reaction behaviour of arylamines with nitroalkenes in the presence of bismuth(iii) triflate: An easy access to 2,3-dialkylquinolines
Ali, Saghir,Gattu, Radhakrishna,Singh, Varun,Mondal, Santa,Khan, Abu T.,Dubey, Gurudutt,Bharatam
supporting information, p. 1785 - 1793 (2020/03/17)
We report the reaction behaviour of arylamines with nitroalkenes in the presence of bismuth(iii) triflate (10 mol%) and diacetoxyiodobenzene (10 mol%). We obtained 2,3-dialkylquinoline derivatives instead of the expected 3-alkylindole derivatives. The present reaction is an alternative approach for the synthesis of 2,3-dialkylquinoline derivatives under milder conditions. Furthermore, we establish the mechanistic pathway by theoretical calculations using Gaussian 09 software [B3LYP/6-311+G(d,p)], which shows that the conventional aza-Michael reaction is preferred over Michael addition. Aliphatic nitroalkenes behave in a different manner than aromatic nitroalkenes. An aza-Michael adduct gives rise to an imine by the elimination of water which may tautomerize to the corresponding enamine. The resulting imine and enamine intermediates react together to afford the desired quinoline derivatives. This protocol has the advantages of consecutive formation of one C-N and two C-C bonds, high regioselectivity, broad substrate-scope and good yields.
A Nickel-Bisdiamine Porous Organic Polymer as Heterogeneous Chiral Catalyst for Asymmetric Michael Addition to Aliphatic Nitroalkenes
Buendia, Mikkel B.,Kegn?s, S?ren,Kramer, S?ren
supporting information, p. 5506 - 5512 (2020/10/23)
We report a polystyrene-incorporated chiral nickel(II)-bisdiamine complex, which is accessible on gram-scale. This metal complex functions as a heterogeneous catalyst for the enantioselective Michael addition between malonates and aliphatic nitroalkenes,
Unprecedented Mechanism of an Organocatalytic Route to Conjugated Enynes with a Junction to Cyclic Nitronates
Streitferdt, Verena,Haindl, Michael H.,Hioe, Johnny,Morana, Fabio,Renzi, Polyssena,von Rekowski, Felicitas,Zimmermann, Alexander,Nardi, Martina,Zeitler, Kirsten,Gschwind, Ruth M.
supporting information, p. 328 - 337 (2018/11/23)
Conjugated enynes as well as cyclic nitronates are crucial building blocks for numerous natural products and pharmaceuticals. However, so far, no common and metal-free synthetic route to both conjugated enynes and cyclic nitronates has been reported. Herein, in situ NMR, labelling studies and theoretical calculations were combined to investigate the mechanism of the unusual triple bond formation towards conjugated enynes. Starting from nitroalkene dimers, first an isoxazolidine-2,5-diol derivative is formed as central intermediate. From this, enynes were generated by a combination of oxidation, dehydration, and retro 1,3-dipolar cycloaddition, whereas for nitronates a base induced intramolecular reorganization is proposed. While the product distribution could be controlled and high yields of nitronate were achieved, only medium to good yields for enynes were obtained due to polymerization losses. Nevertheless, we hope that these mechanistic investigations may provide a basis for further developments of organocatalytic or metal-free preparations of conjugated enynes and nitronates.
CuI-Catalysed Enantioselective Alkyl 1,4-Additions to (E)-Nitroalkenes and Cyclic Enones with Phosphino-Oxazoline Ligands
Shin, Minkyeong,Gu, Minji,Lim, Sung Soo,Kim, Min-Jae,Lee, JuHyung,Jin, HyeongGyu,Jang, Yun Hee,Jung, Byunghyuck
supporting information, p. 3122 - 3130 (2018/07/06)
Catalytic enantioselective conjugate additions of simple alkyl groups to nitroalkenes or cyclic enones that result in the formation of tertiary C–C bonds are described. For these stereoselective addition reactions, new chiral phosphino-oxazoline ligands w
Diaminosilane-functionalized on silicate-stabilised hydrotalcite (MA-HTSi-DA): As potential catalyst for nitro-aldol condensation
Thangaraj, Baskaran,Jayaraj, Christopher,Srinivasan, Radhakrishnan,Ayyamperumal, Sakthivel
, p. 11 - 18 (2015/09/01)
Diaminosilane was introduced into silicate-anion-intercalated hydrotalcite (HT-Si) using a post-synthesis method. The resulting functionalized materials possess surface basicity. The textural properties of the functionalized materials were systematically investigated through powder XRD, FTIR and MAS-NMR studies. The diamine-functionalized materials showed very good catalytic activity for the nitro-aldol condensation of benzaldehyde and nitromethane under solvent-free conditions. The materials showed comparable catalytic activity upon recycling.
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.
Highly efficient iridium-catalyzed asymmetric hydrogenation of β-acylamino nitroolefins
Yan, Qiaozhi,Liu, Man,Kong, Duanyang,Zi, Guofu,Hou, Guohua
supporting information, p. 12870 - 12872 (2014/12/11)
The first highly efficient Ir-catalyzed enantioselective hydrogenation of β-acylamino nitroolefins is reported. This reaction provides straightforward access to chiral β-amino nitroalkanes in high yields and excellent enantioselectivities (up to >99.9% ee) catalyzed by an Ir-(R,R)-f-spiroPhos complex. This journal is
Asymmetric palladium(II)-catalyzed cascade reaction giving quaternary amino succinimides by 1,4-addition and a nef-type reaction
Weber, Manuel,Frey, Wolfgang,Peters, Rene
supporting information, p. 13223 - 13227 (2014/01/06)
Simple starting materials, high-value products: A dinuclear ferrocene-based PdII complex transforms mixtures of racemic N-benzoyl α-amino acids, nitroolefins, acetic anhydride, and manganese acetate into biologically interesting quaternary amin
TRIAZOLIUM CARBENE CATALYSTS AND PROCESSES FOR ASYMMETRIC CARBON-CARBON BOND FORMATION
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Page/Page column 32, (2012/02/02)
Provided herein are chiral triazolium catalysts useful for asymmetric C-C bond formation and processes for their preparation. Also provided are synthetic reactions in which these catalysts are used, in particular, in asymmetric C-C bond formation.
