21232-36-0Relevant academic research and scientific papers
Exploiting the Catalytic Diversity of Short-Chain Dehydrogenases/Reductases: Versatile Enzymes from Plants with Extended Imine Substrate Scope
Roth, Sebastian,Kilgore, Matthew B.,Kutchan, Toni M.,Müller, Michael
, p. 1849 - 1852 (2018)
Numerous short-chain dehydrogenases/reductases (SDRs) have found biocatalytic applications in C=O and C=C (enone) reduction. For NADPH-dependent C=N reduction, imine reductases (IREDs) have primarily been investigated for extension of the substrate range. Here, we show that SDRs are also suitable for a broad range of imine reductions. The SDR noroxomaritidine reductase (NR) is involved in Amaryllidaceae alkaloid biosynthesis, serving as an enone reductase. We have characterized NR by using a set of typical imine substrates and established that the enzyme is active with all four tested imine compounds (up to 99 % conversion, up to 92 % ee). Remarkably, NR reduced two keto compounds as well, thus highlighting this enzyme family's versatility. Using NR as a template, we have identified an as yet unexplored SDR from the Amaryllidacea Zephyranthes treatiae with imine-reducing activity (≤95 % ee). Our results encourage the future characterization of SDR family members as a means of discovering new imine-reducing enzymes.
Chiral diphosphine ddppm-iridium complexes: Effective asymmetric imine hydrogenations at ambient pressures
Dervisi, Athanasia,Carcedo, Cristina,Ooi, Li-Ling
, p. 175 - 183 (2006)
Complexes of the type [Ir(ddppm)(COD)]X were prepared and tested in the asymmetric hydrogenation of a range of imine substrates. Contrary to known iridium catalysts, the ddppm complexes formed efficient catalysts under an atmospheric hydrogen pressure, wh
Iridium-catalyzed asymmetric hydrogenation of imines in supercritical carbon dioxide using phosphite-type ligands
Lyubimov, Sergey E.,Rastorguev, Eugenie A.,Petrovskii, Pavel V.,Kelbysheva, Elena S.,Loim, Nikolay M.,Davankov, Vadim A.
, p. 1395 - 1397 (2011)
A series of chiral phosphite-type ligands has been evaluated in the iridium-catalyzed asymmetric hydrogenation of acyclic arylimines in supercritical CO2. High reactivities (100% conversion in 50-120 min) and enantioselectivities (up to 95%) we
Br?nsted Acid Promoted Regioselective C-3 Arylation and Heteroarylation of Spiro-epoxyoxindoles for the Construction of All Carbon Quaternary Centres: A Detailed Study
Hajra, Saumen,Maity, Subrata,Roy, Sayan,Maity, Ramkrishna,Samanta, Srikrishna
, p. 969 - 987 (2019)
An efficient strategy for the synthesis of all carbon quaternary centres has been developed via Br?nsted acid-promoted highly regioselective intermolecular Friedel–Crafts reactions of heteroarenes or arenes with spiro-epoxyoxindoles. In addition, we have successfully performed the ring opening reaction in relatively cheap condition using water as a solvent. Beneficially, we have utilized the methodology as the key step for the synthesis of advanced precursors of various natural and unnatural indole alkaloids.
Synthesis of Josiphos-type bisphospholane ligands
Hammerer, Tim,Daembkes, Andrea,Francio, Giancarlo,Leitner, Walter,Braun, Wolfgang,Salzer, Albrecht
, p. 2793 - 2797,5 (2012)
Bisphospholane Josiphos-type ligands were synthesized in high yields employing electrophilic and nucleophilic phospholane synthons. Full characterization data including solid-state structures of the diastereomeric ligands are reported. These ligands resul
Chiral carbene-borane adducts: Precursors for borenium catalysts for asymmetric FLP hydrogenations
Lam, Jolie,Günther, Benjamin A. R.,Farrell, Jeffrey M.,Eisenberger, Patrick,Bestvater, Brian P.,Newman, Paul D.,Melen, Rebecca L.,Crudden, Cathleen M.,Stephan, Douglas W.
, p. 15303 - 15316 (2016)
The carbene derived from (1R,3S)-camphoric acid was used to prepare the borane adduct with Piers' borane 7. Subsequent hydride abstraction gave the borenium cation 8. Adducts with 9-BBN and the corresponding (1R,3S)-camphoric acid-derived carbene bearing increasingly sterically demanding N-substituents (R = Me 9, Et 10, i-Pr 11) and the corresponding borenium cations 12-14 were also prepared. These cations were not active as catalysts in hydrogenation, although 9-11 were shown to undergo carbene ring expansion reactions at 50 °C to give species 15-17. The IBOX-carbene precursors 18 and 19 derived from amino alcohols (S)-valinol and (S)-tert-leucinol (R = i-Pr, t-Bu) were used to prepare borane adducts 20-23. Reaction of the carbenes 1,3-dimethylimidazol-2-ylidene (IMe), 1,3-di-iso-propylimidazol-2-ylidene (IPr) 1-benzyl-3-methylimidazol-2-ylidene (IBnMe), 1-methyl-3-phenylimidazol-2-ylidene (IPhMe) and 1-tert-butyl-3-methylimidazol-2-ylidene (ItBuMe) with diisopinocampheylborane (Ipc2BH) gave chiral adducts: (IMe)(Ipc2BH) 24, (IPr)(Ipc2BH) 25, (IBnMe)(Ipc2BH) 26, (IPhMe)(Ipc2BH) 27, and (ItBuMe)(Ipc2BH) 28. Triazolylidene-type adducts including the (10)-phenyl-9-borabicyclo [3.3.2]decane adduct of 1,3,4-triphenyl-1H-1,2,3-triazolium, rac-29 and the 9-BBN derivative of (S)-2-amino-2′-methoxy-1,1′-binaphthalene-1,2,3-triazolium 34a/b were also prepared. In catalytic studies of these systems, while several species were competent catalysts for imine reduction, in general, low enantioselectivities, ranging from 1-20% ee, were obtained. The implications for chiral borenium cation catalyst design are considered.
Tetrathiafulvalene-oxazoline ligands in the iridium catalyzed enantioselective hydrogenation of arylimines
Rethore, Celine,Riobe, Francois,Fourmigue, Marc,Avarvari, Narcis,Suisse, Isabelle,Agbossou-Niedercorn, Francine
, p. 1877 - 1882 (2007)
Cationic iridium complexes based on enantiomerically pure tetrathiafulvalene-oxazoline ligands have been used in the asymmetric hydrogenation of N-(phenylethylidene)aniline. Complete conversions with ee's up to 68% could be reached in the case of the TTF-
Iridium-catalyzed asymmetric reductive amination of ketones using an amidophosphite ligand
Lyubimov,Ozolin,Ivanov, P. Yu.,Maiorov,Velezheva,Davankov
, p. 318 - 321 (2015)
A direct iridium-catalyzed asymmetric reductive amination of ketones using an amidophosphite ligand was accomplished for the first time. A new one-step approach to the preparation of biologically active pyrazinocarbazoles was developed.
Dicationic [(BINAP)Pd(solvent)2]2+[TfO-]2: Enantioselective hydroamination catalyst for alkenoyl-N-oxazolidinones
Li, Kelin,Hii, King Kuok
, p. 1132 - 1133 (2003)
Dicationic (BINAP)palladium(II) complex induced high enantioselectiviies in the addition of primary (and secondary) aromatic amines to α, β-unsaturated oxazolidinones (up to 93% ee).
Enantioselective hydrogenation of imines in ionic liquid/carbon dioxide media
Solinas, Maurizio,Pfaltz, Andreas,Cozzi, Pier Giorgio,Leitner, Walter
, p. 16142 - 16147 (2004)
The enantioselective hydrogenation of N-(1-phenylethylidene)aniline using cationic iridium complexes with chiral phosphinooxazoline ligands was studied as a chemical probe to assess the potential of ionic liquid/carbon dioxide (IL/CO2) media fo
