Aidang Lu

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).

Enantioselective Synthesis of trans-Dihydrobenzofurans via Primary Amine-Thiourea Organocatalyzed Intramolecular Michael Addition

A primary amine-thiourea organocatalyzed intramolecular Michael addition access was developed for the synthesis of trans-dihydrobenzofurans. Under the catalysis of an (R,R)-1,2-diphenylethylamine derived primary amine-thiourea bearing a glucosyl scaffold, the corresponding trans-dihydrobenzofurans were obtained in high yields with excellent level of enantioselectivities (94 to >99% ee). Moreover, an in situ isomerization occurring at high temperature gave good to excellent trans/cis ratios as well (trans/cis: 84/16-96/4).

A Recyclable Organocatalyst for Asymmetric Michael Addition of Acetone to Nitroolefins

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 excellent enantioselectivities (97-99% ee) under mild reaction conditions. Moreover, the catalyst could be recovered via simple phase separation and reused at least five times without any loss of both catalytic activity and stereocontrol.

CCDC 817946: Experimental Crystal Structure Determination

Related Article: Kuang Hu, Tao Liu, A.D.Lu, Yunfeng Liu, Youming Wang, Guiping Wu, Zhenghong Zhou, Chuchi Tang|2011|Eur.J.Org.Chem.||3507|doi:10.1002/ejoc.201100029