Asymmetric Michael Addition of Aldimino Esters with Chalcones Catalyzed by Silver/Xing‐Phos: Mechanism‐Oriented Divergent Synthesis of Chiral Pyrrolines. Issue 30 (16th June 2016)

• Record Type: Journal Article
• Authors: Bai, Xing‐Feng; Li, Li; Xu, Zheng; Zheng, Zhan‐Jiang; Xia, Chun‐Gu; Cui, Yu‐Ming; Xu, Li‐Wen
• Is Part Of: Chemistry. Volume 22:Issue 30(2016)
• Page Start: 10399
• Page End: 10404
• Publication Date: 2016-06-16
• Subjects: asymmetric catalysis -- Michael reaction -- pyrrolines -- silver -- stereodivergent synthesis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201601945
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The mechanism‐oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, aromatic amide‐derived nonbiarylatropisomer/silver (silver/Xing‐Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis ‐Δ(1)‐pyrroline derivatives with up to 98 % ee . Besides the inherent performance of the chiral Ag/Xing‐Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)‐pyrrolines, in which an epimerization of the cis ‐Δ(1)‐pyrrolines to the trans ‐isomers during was revealed. Abstract : Powerful Xing‐Phos ! A series of stereodivergent Δ(1)‐pyrroline derivatives was achieved with excellent chemo‐, diastereo‐, and enantioselectivities (up to 98 % ee ) by the silver/Xing‐Phos‐catalyzed Michael addition of glycine aldimino esters to chalcones with the aid of an acidic or basic workup (see scheme; DBU=1, 8‐diazabicycloundec‐7‐ene).