65939-64-2Relevant academic research and scientific papers
Organocatalytic enantio- and diastereoselective synthesis of 3,5-disubstituted prolines
Ria?o, Iker,Díaz, Estibaliz,Uria, Uxue,Reyes, Efraím,Carrillo, Luisa,Vicario, Jose L.
supporting information, p. 2330 - 2333 (2016/02/18)
The asymmetric synthesis of substituted pyrrolidines has been accomplished using a novel organocatalytic cyclization reaction promoted by a Cinchona alkaloid based primary amine. The reaction proceeds smoothly yielding pyrrolidine-2,2-dicarboxylates after in situ diastereoselective reduction with high levels of enantioselection. Furthermore, these adducts could be easily transformed into N-protected disubstituted prolines through the base-promoted diastereoselective C → N alkoxycarbonyl transfer reaction.
Rapid synthesis of substituted pyrrolines and pyrrolidines by nucleophilic ring closure at activated oximes
Chandan, Nandkishor,Thompson, Amber L.,Moloney, Mark G.
, p. 7863 - 7868 (2013/07/05)
Substituted pyrrolines are available by ring closure initiated by direct nucleophilic attack of stabilized enolates at the nitrogen of oximes activated with a leaving group, in a process which effectively out-competes the more usual Beckmann rearrangement. Subsequent reduction provides diastereoselective access to the corresponding pyrrolidines. This provides a rapid route to saturated heterocyclic systems from readily available precursors.
The Synthesis and Chemistry of Azolenines. Part 4. Preparation and Rearrangement of some 3,5-Diaryl-2H-pyrrole-2,2-dicarboxylic Esters
Sammes, Michael P.,Chung, Margaret W. L.,Katritzky, Alan R.
, p. 1773 - 1780 (2007/10/02)
Oxidation of diethyl 3,5-diaryl-3,4-dihydro-2H-pyrrole-2,2-dicarboxylates (3) with chloranil in refluxing xylene gives not the 3,5-diaryl-2H-pyrrole-2,2-dicarboxylates (4) as reported by an earlier group, but instead the rearranged, isomeric, 1H-pyrrole-1,2-dicarboxylates (5). 2H-Pyrroles (4) may be obtained from the dihydropyrroles (3) using DDQ in benzene at room temperature; they rearrange to the isomers (5) in boiling xylene via an acyl -sigmatropic shift from carbon to nitrogen, a novel process in the 2H-pyrrole series.Thermal analyses indicate that the rearrangement is concerted with negligible charge separation in the transition state.Other novel 3,5-diaryl-1H-pyrrole-2-carboxylic acid derivatives are described.
Etude i.r. et NMR de diaryl-2,4 diethoxycarbonyl-5,5Δ1pyrrolines
Robert, J. F.,Koch, J.,Xicluna, A.,Panouse, J. J.
, p. 535 - 542 (2007/10/02)
The spectroscopic properties (i.r., NMR) of 2,4-diaryl-5,5-diethoxycarbonyl-Δ1-pyrrolines has been studied.Chemical shifts and coupling constants of pyrrolinic protons are affected by effect of substitution on phenyl rings.In all cases, we have noted the conservation of magnetic non-equivalence of ethyl ester and methylene groups.Examination of these NMR data gives conformational approach of these pyrrolines.
