Cinchona alkaloid-derived chiral bifunctional thiourea organocatalysts were synthesized and applied in the Michael addition between nitromethane and chalcones with high ee and chemical yields.
Synthesis of a New N-Diaminophosphoryl-N′-[(2S)-2-pyrrolidinylmethyl]thiourea as a Chiral Organocatalyst for the Stereoselective Michael Addition of Cyclohexanone to Nitrostyrenes and Chalcones - Application in Cascade Processes for the Synthesis of Polyc
作者:Carlos Cruz-Hernández、Eduardo Martínez-Martínez、Perla E. Hernández-González、Eusebio Juaristi
DOI:10.1002/ejoc.201801339
日期:2018.12.31
novel chiralthiourea containing a segment of privileged (2S)‐2‐pyrrolidinylmetan‐amine as well as a hydrophobic phosphoramide framework is described. The new organocatalyst exhibited good performance in asymmetricMichaeladditions, in a variety of systems including the formal [3+3] cyclization of cyclohexanone with arylidenepyruvates through a cascade process, which involves the asymmetric Michael
Highly efficient modular metal-free synthesis of 3-substituted 2-quinolones
作者:Alexander V. Aksenov、Alexander N. Smirnov、Nicolai A. Aksenov、Inna V. Aksenova、Asiyat S. Bijieva、Michael Rubin
DOI:10.1039/c4ob02131b
日期:——
A modular approach to 3-substituted 2-quinolones via a cascade annulation reaction between 4-nitroketones and hydrazines has been developed.
通过4-硝基酮和肼之间的级联环化反应,已经开发出一种3-取代2-喹啉酮的模块化方法。
Synthesis of 3,4‐Dihydro‐2
<i>H</i>
‐Pyrroles from Ketones, Aldehydes, and Nitro Alkanes via Hydrogenative Cyclization
作者:Barbara Klausfelder、Patricia Blach、Niels de Jonge、Rhett Kempe
DOI:10.1002/chem.202201307
日期:2022.8.22
developed and employed for the synthesis of 3,4-dihydro-2H-pyrroles via hydrogenation and subsequent cyclization of nitro ketones. The catalyst was identified from a library of 24 heterogeneous catalysts. The key to our hydrogenation/cyclization reaction is the tolerance of aldehydes and ketones as functional groups and the ability to hydrogenate aliphaticnitrocompounds efficiently.
Enantiomerically pure carbamate-monoprotected trans-cyclohexane-1,2-diamines are used as chiral organocatalysts for the addition of aryl ketones and acetone to nitroalkenes to give enantioenriched beta-substituted gamma-nitroketones. The reaction was performed in the presence of 3,4-dimethoxybenzoic acid as an additive, in chloroform as the solvent at room temperature, achieving enantioselectivities up to 96%. Theoretical calculations are used to justify the observed sense of the stereoinduction. (C) 2015 Elsevier Ltd. All rights reserved.