Gd(III)-Catalyzed Regio‑, Diastereo‑, and Enantioselective [4 + 2] Photocycloaddition of Naphthalene Derivatives

• Published in: Journal of the American Chemical Society Vol. 146; no. 25; pp. 16982 - 16989
• Main Authors: Li, Muzi, Huang, Xu-Lun, Zhang, Zuo-Yu, Wang, Zhiping, Wu, Zhuo, Yang, Hui, Shen, Wen-Jie, Cheng, Yuan-Zheng, You, Shu-Li
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 26.06.2024; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; ASYMMETRIC DEAROMATIZATION; CYCLOADDITION; LEWIS-ACID CATALYSIS; VISIBLE-LIGHT PHOTOREDOX; COMPLEXES
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.4c05288

Catalytic asymmetric dearomatization (CADA) reactions have evolved into an efficient strategy for accessing chiral polycyclic and spirocyclic scaffolds from readily available planar aromatics. Despite the significant developments, the CADA reaction of naphthalenes remains underdeveloped. Herein, we report a Gd­(III)-catalyzed asymmetric dearomatization reaction of naphthalene with a chiral PyBox ligand via visible-light-enabled [4 + 2] cycloaddition. This reaction features application of a chiral Gd/PyBox complex, which regulates the reactivity and selectivity simultaneously, in excited-state catalysis. A wide range of functional groups is compatible with this protocol, giving the highly enantioenriched bridged polycycles in excellent yields (up to 96%) and selectivity (up to >20:1 chemoselectivity, >20:1 dr, >99% ee). The synthetic utility is demonstrated by a 2 mmol scale reaction, removal of directing group, and diversifications of products. Preliminary mechanistic experiments are performed to elucidate the reaction mechanism.