Inverse‐Electron‐Demand Palladium‐Catalyzed Asymmetric [4+2] Cycloadditions Enabled by Chiral P, S‐Ligand and Hydrogen Bonding. (3rd July 2019)

• Record Type: Journal Article
• Authors: Wang, Ya‐Ni; Xiong, Qin; Lu, Liang‐Qiu; Zhang, Qun‐Liang; Wang, Ying; Lan, Yu; Xiao, Wen‐Jing
• Is Part Of: Angewandte Chemie. Volume 131:Number 32(2019)
• Page Start: 11129
• Page End: 11133
• Publication Date: 2019-07-03
• Subjects: Cycloaddition -- Heterocyclen -- P, S-Liganden -- Palladium -- Wasserstoffbrücken; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201905993
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Catalytic asymmetric cycloadditions of ambident Pd‐containing dipolar species with nucleophilic dipolarophiles, namely, inverse‐electron‐demand cycloadditions, are challenging and underdeveloped. Possibly, the inherent linear selectivity of Pd‐catalyzed intermolecular allylations and the lack of efficient chiral ligands are responsible for this limitation. Herein, two cycloadditions of such intermediates with deconjugated butenolides and azlactones were accomplished by using a novel chiral hybrid P, S‐ligand and hydrogen bonding. By doing so, highly functionalized, optically active dihydroquinol‐2‐ones were produced with generally high reaction efficiencies and selectivities. Preliminary DFT calculations were performed to explain the high enantio‐ and diastereoselectivities. Abstract : Bedarfsgerecht : Mithilfe von chiralen P, S‐Liganden und Wasserstoffbrückenwechselwirkungen gelangen erstmals asymmetrische [4+2]‐Cycloadditionen mit inversem Elektronenbedarf. Optisch aktive, hochfunktionalisierte Hydrochinolin‐2‐one wurden in guter Ausbeute mit ausgezeichneter Stereokontrolle aus leicht verfügbaren Ausgangsmaterialien hergestellt.