l-proline-derived bifunctional organocatalyst. This strategy allows the enantioselective synthesis of a variety of 3-alkyl-3-hydroxyindolin-2-ones with a stereogenic quaternary carbon center in excellent yields with good to excellent enantiomeric excess. The method has been applied to the enatioselective synthesis of (S)-convolutamydine A successfully.
the isatin-acetone reaction at higher temperatures without compromising enantioselectivity is reported. Kamlet-Taftbasicity (β) and proticity (α) of solvents were found to be crucial in describing the solubility of isatin and performance of L-leucinol organocatalyst and informed the choice of solvent for transfer to flow.
Dipeptide-Catalyzed Asymmetric Aldol Condensation of Acetone with (N-Alkylated) Isatins
作者:Gianluigi Luppi、Pier Giorgio Cozzi、Magda Monari、Bernard Kaptein、Quirinus B. Broxterman、Claudia Tomasini
DOI:10.1021/jo050257l
日期:2005.9.1
The aldol condensation of acetone with several isatins is described. The desired compound was obtained in quantitative yield and with good enantioselectivities up to 77%. The best results were obtained with 10 mol % H-d-Pro-l-β3-hPhg-OBn as a catalyst, resulting in the preferential formation of the (R)-enantiomer. The absolute configuration of the newly formed chiral center has been assigned by an
Solvent-free asymmetric aldol reaction organocatalyzed by (S)-proline-containing thiodipeptides under ball-milling conditions
作者:José G. Hernández、Víctor García-López、Eusebio Juaristi
DOI:10.1016/j.tet.2011.10.093
日期:2012.1
protocol for the asymmetric aldolreaction between cyclohexanone and cyclopentanone with various aromatic aldehydes using a novel series of (S)-proline-containing dipeptides and thiodipeptides 1a–f as organocatalysts is reported. In general, (S)-proline-containing thiodipeptides proved to be better organocatalysts relative to their analogous amides. In particular, thiodipeptide (S,S)-1d catalyzed the stereoselective
trans-4-Hydroxy-l-prolinamide as an efficient catalyst for direct asymmetric aldol reaction of acetone with isatins
作者:Geeta Devi Yadav、Surendra Singh
DOI:10.1016/j.tetasy.2016.04.008
日期:2016.7
Prolinamide (2S,4R)-4-hydroxy-N-((S)-1-phenylethyl)pyrrolidine-2-carboxamide was found to be an efficient organocatalyst (10 mol %) for the direct asymmetric aldol reactions of isatins with acetone at -35 degrees C in THF and afforded the product in 79% yield with 74% ee. We have generalised the methodology for the direct asymmetric aldol reaction between isatin derivatives and acetone, and the corresponding aldol products were obtained in high yields (up to 99%) and with moderate enantioselectivities (up to 80%). This method has been applied to the enantioselective synthesis of (S)-convolutamydine. (C) 2016 Elsevier Ltd. All rights reserved.