4-Aminothioureaprolinal dithioacetal 4a is a highlyefficientcatalyst for the asymmetric Michaeladdition of ketones and aldehydes to nitroolefins requiring only 3 mol-% catalyst loading. The reactions proceeded smoothly and gave syn selective adducts with excellent yields (up to 98 % yield), diastereoselectivity (up to >99:1 dr), and enantioselectivity (up to 99 % ee) under solvent free conditions
Based on different chiral diamine skeletons, a series of bifunctional primary amine-thiophosphoramides were synthesized and screened as the catalysts for the asymmetric Michael addition of acetone to both aromatic and aliphatic nitroolefins. Under the catalysis of a thiophosphoramide derived from 1,2-diphenylethane-1,2-diamine, the corresponding adducts were obtained in high yields (up to >99%) with
Readily Accessible 9-epi-amino Cinchona Alkaloid Derivatives Promote Efficient, Highly Enantioselective Additions of Aldehydes and Ketones to Nitroolefins
作者:Séamus H. McCooey、Stephen J. Connon
DOI:10.1021/ol0628006
日期:2007.2.1
from commercially available starting materials, have been shown to promote highly enantio- and diastereoselective Michael-type addition reactions between enolizable carbonyl compounds and nitroalkenes of broad scope. The influence of both the absolute and relative stereochemistry at C-9 on catalyst performance has also been assessed. [reaction: see text].
Novel pyrrolidine-thiohydantoins/thioxotetrahydropyrimidinones as highly effective catalysts for the asymmetric Michael addition
作者:Christoforos G. Kokotos、Dimitris Limnios、Despoina Triggidou、Maria Trifonidou、George Kokotos
DOI:10.1039/c0ob01083a
日期:——
The synthesis of novel organocatalysts consisting of a pyrrolidine moiety and a thiohydantoin or a thioxotetrahydropyrimidinone ring is described. The compound combining the pyrrolidine with the thioxotetrahydropyrimidinone was found to be a highly effective catalyst for the Michael reaction. Low catalyst loadings (1–2.5%) can be employed leading to quantitative yields and excellent stereoselectivities
Assessment of the organocatalytic activity of chiral l-Proline-based Deep Eutectic Solvents based on their structural features
作者:Matteo Tiecco、Diego A. Alonso、Diego Ros Ñíguez、Gianluca Ciancaleoni、Gabriela Guillena、Diego J. Ramón、Alberto Apio Bonillo、Raimondo Germani
DOI:10.1016/j.molliq.2020.113573
日期:2020.9
capabilities, since their properties are truly tuneable. In this paper, l-Proline-based Chiral Deep Eutectic Solvents (CDESs) were prepared and used as green and organocatalyticreactionmedia in a probe asymmetricMichael addition; in this reaction the l-Proline acts as solvent component as well as chiral organocatalyst. The results were analysed with NMR studies taking in account the availability of the