115914-08-4Relevant articles and documents
Visible Light-Mediated Synthesis of Enantiopure γ-Cyclobutane Amino and 3-(Aminomethyl)-5-phenylpentanoic Acids
Kerres, Sabine,Plut, Eva,Malcherek, Simon,Rehbein, Julia,Reiser, Oliver
supporting information, (2019/02/07)
A visible light-mediated [2+2] photocycloaddition of amide-linked dienes using [Ir(dtb-bpy)(dF(CF3)ppy)2]PF6 as triplet sensitizer was applied to generate a variety of N-tert-butyl, N-benzyl- and N-tert-butoxycarbonyl-protected 3-azabicyclo[3.2.0]heptan-2-ones in good yields and with good diastereoselectivity. Density functional theory calculations shed light on the conformational prerequisites for the [2+2] photocycloaddition. The bicyclic key structures could be readily transformed into γ-cyclobutane amino acids. For the obtained racemic 3-phenyl-2-aminocyclobutane-1-carboxylic acid the resolution with chiral oxazolidin-2-one is demonstrated to allow access to both enantiomers. Alternatively, a chiral auxiliary approach led as well to the enantiomerically pure target compound. Finally, the synthesis of either enantiomer of 3-(aminomethyl)-5-phenylpentanoic acid, the racemate being described as an anticonvulsant, is described.
Metal-free, mild, nonepimerizing, chemo- and enantio- or diastereoselective N-alkylation of amines by alcohols via oxidation/imine-iminium formation/reductive amination: A pragmatic synthesis of octahydropyrazinopyridoindoles and higher ring analogues
Khan, Imran A.,Saxena, Anil K.
, p. 11656 - 11669 (2014/01/06)
A mild step and atom-economical nonepimerizing chemo- and enantioselective N-alkylating procedure has been developed via oxidation/imine-iminium formation/reduction cascade using TEMPO-BAIB-HEH-Bronsted acid catalysis in DMPU as solvent and a stoichiometric amount of amine. The optimized conditions were further extended for the nonenzymatic kinetic resolution of the chiral amine thus formed under nonenzymatic in situ hydrogen-transfer conditions using VAPOL-derived phosphoric acid (VAPOL-PA) as the Bronsted acid catalyst. The enantioselective cascade of the presented reaction was successfully utilized in the synthesis of octahydropyrazinopyridoindole and its higher ring analogues.
Stereoselective 5-exo-trig radical cyclization in the enantioselective synthesis of Pregabalin
Rodríguez, Verónica,Quintero, Leticia,Sartillo-Piscil, Fernando
, p. 4305 - 4308 (2008/02/12)
A practical stereoselective 5-exo-trig radical cyclization procedure was developed in order to prepare enantiomerically pure GABA derivative precursors (4-alkyl-pyrrolidin-2-ones). This procedure allows much more rapid access to optically pure GABA derivatives, such as the powerful antiepileptic agent (S)-(+)-3-aminomethyl-5-methylhexanoic acid (Pregabaline).
