Highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins catalyzed by a chiral glucose-based bifunctional secondary amine-thiourea catalyst
A novel bifunctional thiourea bearing a saccharide-scaffold and a secondary amino group was synthesized, and was proven to be an effective organocatalyst for the asymmetric Michael reaction of cyclohexanone to both aryl and alkyl nitroolefins. The corresponding adducts were obtained with excellent diastereo- (up to >99/1 dr) and enantioselectivities (up to 97% ee).
Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate–thiourea hybrid with mechanistic DFT analysis
作者:Chandra S. Azad、Imran A. Khan、Anudeep K. Narula
DOI:10.1039/c6ob02158a
日期:——
core scaffold were synthesized and examined as catalysts for the asymmetricMichael addition reaction of aryl/alkyl trans-β-nitrostyrenes over cyclohexanone and other Michael donors having active methylene. Excellent enantioselectivities (<95%), diastereoselectivities (<99%), and yields (<99%) were attained undersolvent free conditions using 10 mol% of 1d0. The obtained results were explained through
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
Simple Chiral PyrrolidineâPyridine-Based Catalysts for Highly Enantioselective Michael Addition to Nitro Olefins
作者:Da-Zhen Xu、Sen Shi、Yongmei Wang
DOI:10.1002/ejoc.200900716
日期:2009.10
of chiral pyrrolidine–pyridine-based organocatalysts, available from commercially available starting materials, have been synthesized and shown to be very effective catalysts for the asymmetric Michaeladdition reactions of cyclic/acyclic/aromatic ketones and an aldehyde with nitro olefins, giving excellent yields (up to 99 %), diastereoselectivities (syn/anti = 99:1), and enantioselectivities (up
A surfactant-type asymmetric organocatalyst (STAO) catalyzed highly efficient Michael addition to nitroalkenes with high stereoselectivities in water without using any organic solvents or additional additives.