A novel and effective organocatalytic system consisting of pyrrolidinyl-thioimidazole and a chiral thioureido acid efficiently catalyzed the asymmetric Michaeladdition reactions of ketones to nitroolefins to afford the adducts with high diastereoselectivities (up to 99 : 1) and excellent enantioselectivities (up to 99% ee).
A Homo-Proline Tetrazole as an Improved Organocatalyst for the Asymmetric Michael Addition of Carbonyl Compounds to Nitro-Olefins
作者:Steven V. Ley、Claire E. Mitchell、Alexander J. Cobb
DOI:10.1055/s-2005-862392
日期:——
A new homo-proline tetrazole derivative 7 has been prepared and shown to have improved properties for achieving asymmetric Michaeladdition of carbonyl compounds to nitro-olefins.
Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction
作者:Chandan K. Mahato、Sayan Mukherjee、Mrinalkanti Kundu、Animesh Pramanik
DOI:10.1021/acs.joc.8b02393
日期:2019.1.18
Pyrrolidine-oxadiazolone based organocatalysts are envisaged, synthesized, and utilized for asymmetric Michael reactions. Results of the investigations suggest that some of the catalysts are indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to 99%) in high chemical yields (up to 97%) often in short reaction time. As an extension, one enantiopure Michael adduct has been utilized to
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].
Peptidomimetic organocatalysts: efficient Michael addition of ketones onto nitroolefins with very low catalyst loading
作者:Srivari Chandrasekhar、Chintakunta Praveen Kumar、Togapur Pavan Kumar、Kothapalli Haribabu、Bharatam Jagadeesh、Jerripothula K. Lakshmi、Prathama S. Mainkar
DOI:10.1039/c4ra04165h
日期:——
The syntheses of two novel peptidomimetic triazole-based organocatalysts that work for the asymmetric conjugate addition of cyclohexanone to nitroolefins are described. The catalysts worked with very low loading (0.5 mol%) in the absence of any additives to provide high diastereo- and enantio-selectivities.