Enantio- and Diastereoselective Asymmetric Addition of 1,3-DicarbonylCompounds to Nitroalkenes in a Doubly Stereocontrolled MannerCatalyzed by Bifunctional Rosin-Derived Amine Thiourea Catalysts

摘要

Starting from commercially available natural rosin derivatives, a class of bifunctional rosin-derivedamine thiourea catalysts were designed and synthesized. The doubly stereocontrolled asymmetricaddition of a variety of 1,3-dicarbonyl compounds to nitroalkenes was investigated. These rosin-derived chiral thioureas have been shown to serve as effective catalysts for this double-sterecontrolledorganocatalytic process by the investigation of the efficacy of the thiourea catalysts in comparisonwith other thiourea catalysts reported. In addition, these chiral thiourea ligands are easily available.Furthermore, the rosin-derived tertiary amine-thiourea was also revealed to be highly efficient forconstruction of contiguous stereogenetic centers containing an asymmetric quaternary carbon by theMichael reaction of α-substituted β-ketoesters to nitroalkenes.