Asymmetric Michael Addition Induced by the Anion of an Imidazolium Salt
作者:Vincent Gauchot、Julien Gravel、Andreea R. Schmitzer
DOI:10.1002/ejoc.201201068
日期:2012.11
We describe the application of a chiral catalytic imidazoliumsalt derived from trans-L-hydroxyproline, the anion being the catalytic entity, as a catalyst for the asymmetricMichaeladdition. We report the first example of a catalytic Michaeladdition using this type of catalyst, leading to excellent yields (up to 99 %) and good selectivities (up to 99:1 dr, up to 82 % ee).
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].
Organocatalytic Direct Michael Reaction of Ketones and Aldehydes with β-Nitrostyrene in Brine
作者:Nobuyuki Mase、Kaori Watanabe、Hidemi Yoda、Kunihiko Takabe、Fujie Tanaka、Carlos F. Barbas
DOI:10.1021/ja060338e
日期:2006.4.1
We have developed a direct, asymmetric Michael reaction that can be performed in brine or seawater without addition of organic solvents. A bifunctional catalyst with long hydrophobic alkyl chains efficiently catalyzed Michael reactions and afforded the desired products in excellent yield with high enantiomeric excess, even when only an equal molar ratio of the donor to acceptor was used.