Inverse‐Electron‐Demand Palladium‐Catalyzed Asymmetric [4+2] Cycloadditions Enabled by Chiral P, S‐Ligand and Hydrogen Bonding. Issue 32 (4th 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 international edition. Volume 58:Issue 32(2019)
• Page Start: 11013
• Page End: 11017
• Publication Date: 2019-07-04
• Subjects: cycloaddition -- heterocycles -- P, S ligand -- hydrogen bonding -- palladium; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201905993
• Languages: English
• ISSNs: 1433-7851

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 : By popular demand : With the help of chiral P, S‐ligands and hydrogen‐bonding interactions, inverse‐electron‐demand asymmetric [4+2] cycloadditions were accomplished for the first time. A variety of optically active, highly functionalized hydroquinolin‐2‐ones were produced in good yields with excellent stereocontrol from readily available starting materials.