Organocatalytic Enantioselective Synthesis of Seven‐Membered Ring with Inherent Chirality

• Published in: Angewandte Chemie International Edition Vol. 63; no. 8; pp. e202319289 - n/a
• Main Authors: Li, Jia‐Hao, Li, Xiao‐Kai, Feng, Jia, Yao, Wang, Zhang, Huan, Lu, Chuan‐Jun, Liu, Ren‐Rong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 19-02-2024
• Edition: International ed. in English
• Subjects: 7-Membered Ring; Chemical synthesis; Chiral Phosphoric Acid; Chirality; Condensation; Enantiomers; Enantioselective Synthesis; Ethers; Inherent Chirality; Ketones; Phosphoric acid; Enantioselective Synthesis; Chiral Phosphoric Acid; Condensation; 7-Membered Ring; Inherent Chirality
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202319289

Inherent chirality is used to describe chiral cyclic molecules devoid of central, axial, planar, or helical chirality and has tremendous applications in chiral recognition and enantioselective synthesis. Catalytic and divergent syntheses of inherently chiral molecules have attracted increasing interest from chemists. Herein, we report the enantioselective synthesis of inherently chiral tribenzocycloheptene derivatives via chiral phosphoric acid (CPA)‐catalyzed condensation of cyclic ketones and hydroxylamines. This chemistry paves the way to accessing the less stable derivatives of 7‐membered rings with inherent chirality. A series of chiral tribenzocycloheptene oxime ethers was synthesized in good yields (up to 97 %) with excellent enantioselectivities (up to 99 % ee).
Developing efficient protocols to construct inherent chirality is highly desirable owing to its tremendous application in chiral recognition and enantioselective synthesis. Herein, we report the first enantioselective synthesis of 7‐membered inherently chiral derivatives via chiral phosphoric acid‐catalyzed condensation. This chemistry highlights the broad substrate scope and excellent stereocontrol (up to 99 % ee).