Synlett 2024; 35(12): 1338-1344
DOI: 10.1055/a-2184-6373
synpacts

Pd-catalyzed Stereodivergent [4+2] Annulation to Access [6.7]-Fused N-Heterocycles

Zhan-Cai Ma
,
Yuan Huang
The authors are grateful for financial support provided by the National Natural Science Foundation of China (22001203), the Key Research and Development Plan of Shaanxi Province (2023-YBSF-186), and the funds from Xi’an Jiaotong University (XJTU).


Abstract

Stereodivergent synthesis of N-heterocycle frameworks bearing 1,3-nonadjacent stereogenic centers through a single transformation remains a high-priority challenge in organic synthesis. Herein, we highlight our recent discovery of stereodivergent access to such useful structural motifs using Pd-catalyzed [4+2] annulation reactions of vinyl benzoxazinaones and seven-membered cyclic N-sulfonyl aldimines. A wide range of N-heterocycles with 1,3-nonadjacent stereogenic centers were obtained in high efficiency and stereodivergency. Importantly, the polarity of solvents was found to play a key role in switching the diastereoselectivity. Furthermore, good enantioselectivities of these reactions were achieved by the employment of commercially available Wingphos as the chiral ligand.



Publication History

Received: 06 September 2023

Accepted after revision: 29 September 2023

Accepted Manuscript online:
29 September 2023

Article published online:
30 October 2023

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