372967-45-8Relevant articles and documents
Hydrogen-Borrowing Alkylation of 1,2-Amino Alcohols in the Synthesis of Enantioenriched γ-Aminobutyric Acids
Hall, Christopher J. J.,Goundry, William R. F.,Donohoe, Timothy J.
, p. 6981 - 6985 (2021/03/01)
For the first time we have been able to employ enantiopure 1,2-amino alcohols derived from abundant amino acids in C?C bond-forming hydrogen-borrowing alkylation reactions. These reactions are facilitated by the use of the aryl ketone Ph*COMe. Racemisation of the amine stereocentre during alkylation can be prevented by the use of sub-stoichiometric base and protection of the nitrogen with a sterically hindered triphenylmethane (trityl) or benzyl group. The Ph* and trityl groups are readily cleaved in one pot to give γ-aminobutyric acid (GABA) products as their HCl salts without further purification. Both steps may be performed in sequence without isolation of the hydrogen-borrowing intermediate, removing the need for column chromatography.
Chiral N-heterocyclic carbene-iridium complexes for asymmetric reduction of prochiral ketimines
Kathuria, Lakshay,Samuelson, Ashoka G.
supporting information, (2020/12/28)
Enantioselective reduction of imines to the corresponding chiral secondary amines has been studied using a series of chiral half-sandwich iridium complexes. Chiral N-heterocyclic carbene (NHC) ligands in these complexes were synthesized from readily available, naturally occurring amino acids. Inexpensive phenylsilane was used as a convenient hydrogen donor. Under the optimized conditions, Ir-NHC complexes could reduce ketimines in good yields, albeit with moderate enantiomeric excess (ee). The phenylglycine derived chiral NHC was shown to give the best Ir catalyst and it also gave the maximum ee compared to catalysts prepared from other NHCs in this series. The opposite enantiomer of the reduction product was always obtained while using the Ir complex bearing a valine based NHC. The yields were consistently high with a variety of imine substrates having different steric and electronic demands.
MANGANESE-CATALYSED HYDROGENATION OF ESTERS
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Page/Page column 34; 37; 38, (2019/08/06)
The present invention relates to the field of catalytic hydrogenation and, more particularly, to methods of manganese-catalysed hydrogenation of esters to alcohols. Advantageously, where the esters are chiral, the hydrogenations proceed with high or complete stereochemical integrity..
Regioselective Fluorination of α-Hydroxy-β-aminophosphonates by Using PyFluor
Ka?mierczak, Marcin,Kubicki, Maciej,Koroniak, Henryk
, p. 3844 - 3852 (2018/07/31)
We report a simple protocol for the synthesis of α-fluoro-β-aminophosphonates by the regioselective fluorination of α-hydroxy-β-aminophosphonates under mild conditions. The fluorination reactions were mediated by the PyFluor reagent and occurred with the retention of configuration. The main products of this reaction were a series of α-fluoro-β-aminophosphonates, which can be used as precursors in the preparation of medicinally important compounds (e.g., dipeptide analogues).
Manganese Catalyzed Hydrogenation of Enantiomerically Pure Esters
Widegren, Magnus B.,Clarke, Matthew L.
, p. 2654 - 2658 (2018/05/17)
A manganese-catalyzed hydrogenation of esters has been accomplished with TONs up to 1000, using cheap, environmentally benign, potassium carbonate and simple alcohols as activator and solvent, respectively. The weakly basic conditions lead to good functional group tolerance and enable the hydrogenation of enantiomerically enriched α-chiral esters with essentially no loss of stereochemical integrity.
Rapid Asymmetric Synthesis of Disubstituted Allenes by Coupling of Flow-Generated Diazo Compounds and Propargylated Amines
Poh, Jian-Siang,Makai, Szabolcs,von Keutz, Timo,Tran, Duc N.,Battilocchio, Claudio,Pasau, Patrick,Ley, Steven V.
supporting information, p. 1864 - 1868 (2017/02/05)
We report herein the asymmetric coupling of flow-generated unstabilized diazo compounds and propargylated amine derivatives, using a new pyridinebis(imidazoline) ligand, a copper catalyst and base. The reaction proceeds rapidly, generating chiral allenes in 10–20 minutes with high enantioselectivity (89–98 % de/ee), moderate yields and a wide functional group tolerance.
A - And B -fluorinated aminophosphonates-Synthesis and properties
Ka?mierczak, Marcin,Kubicki, Maciej,Koroniak, Henryk
, p. 459 - 468 (2016/04/09)
Interest in synthesis of fluorinated aminophosphonates has grown significantly in recent years due to their promising applications in medicinal and bioorganic chemistry. We report herein efficient and general methods for the synthesis of α- and β-monofluo
Access to Atropisomerically En-riched Biaryls by the Coupling of Aryllithiums with Arynes under Control by Homochiral Oxazolines
Yalcouye, Boubacar,Berthelot-Bréhier, Ana?s,Augros, David,Panossian, Armen,Choppin, Sabine,Chessé, Matthieu,Colobert, Fran?oise,Leroux, Frédéric R.
supporting information, p. 725 - 732 (2017/01/18)
We report the preparation of axially stereoenriched biphenyls by the coupling of in situ generated aryllithiums and arynes using chiral oxazoline auxiliaries. The design of the aryne precursors, the choice of oxazoline and the reaction conditions were key to accessing the desired, highly substituted, atropisomerically enriched biarylic products. In one case, the two atropo-diastereomers could be obtained in isomerically pure form by column chromatographic separation and their absolute configurations established by X-ray crystallography. The stereoselectivity of the reaction seems to be governed by subtle parameters.
Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds
Berger, Gilles,Gelbcke, Michel,Cau?t, Emilie,Luhmer, Michel,Nève, Jean,Dufrasne, Fran?ois
supporting information, p. 545 - 548 (2013/02/23)
A new method for the synthesis of 15N-labeled chiral β-diamines from a common precursor, either optically pure amino acids or anti-β-amino alcohols, is reported. The two diastereomeric series of vicinal diamines are produced through the nucleophilic ring opening of activated chiral aziridines. 15N was introduced by means of [ 15N]-benzylamine, prepared from 15NH4Cl. The final compounds are highly valuable because [1H-15N] NMR is considered a powerful tool for studying the chemical properties of platinum-based complexes.
Parallel kinetic resolution of acyclic γ-amino-α,β- unsaturated esters: Application to the asymmetric synthesis of 4-aminopyrrolidin-2-ones
Davies, Stephen G.,Lee, James A.,Roberts, Paul M.,Thomson, James E.,Yin, Jingda
, p. 218 - 221 (2012/03/08)
Conjugate addition of a 50:50 pseudoenantiomeric mixture of lithium (R)-N-benzyl-N-(α-methylbenzyl)amide and lithium (S)-N-3,4- dimethoxybenzyl-N-(α-methylbenzyl)amide to a range of racemic acyclic γ-amino-α,β-unsaturated esters (derived from the corresponding α-amino acids) effects their efficient parallel kinetic resolution, allowing the preparation of enantiopure β,γ-diamino esters. The β,γ-diamino ester products of these reactions are readily converted into the corresponding substituted 4-aminopyrrolidin-2-ones via N-debenzylation and cyclization.
