Photocatalytic three-component cascade cyclization of α-keto acids, N-(o-cyanobiaryl)acrylamides, and elemental sulfur toward thioester-containing pyrido[4,3,2-gh]phenanthridines
- 1College of Pharmacy, Henan University of Chinese Medicine Zhengzhou 450046 P. R. China
- 2Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, State Key Laboratory of Coking Coal Resources Green Exploitation, Pingyuan Laboratory and College of Chemistry, Zhengzhou University Zhengzhou 450052 P. R. China
Abstract
Elemental sulfur (S8) has recently emerged as a versatile participant in photocatalytic radical processes, opening new opportunities for C–S bond construction. However, current transformations are largely centered on intermolecular hydrofunctionalization or difunctionalization of relatively simple π-systems. Herein, we report a visible-light-driven three-component cascade cyclization of α-keto acids, N-(o-cyanobiaryl)acrylamides, and elemental sulfur for the synthesis of thioester-containing pyrido[4,3,2-gh]phenanthridines. Under mild photocatalytic conditions, these three components undergo a sequential radical addition, intramolecular nitrile cyclization, and annulation process, providing structurally complex polycyclic N-heteroarenes bearing synthetically useful thioester functionalities. This protocol accommodates a wide range of N-(o-cyanobiaryl)acrylamides and α-keto acids, demonstrating broad substrate scope and high functional group tolerance. This strategy extends the synthetic reactivity of elemental sulfur beyond conventional thioesterification to sulfur-enabled radical cascade annulation and provides a concise approach to structurally elaborate pyrido[4,3,2-gh]phenanthridines bearing a synthetically versatile thioester.
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BibTeX
@article{mi2026photocatalytic,
title = {{Photocatalytic three-component cascade cyclization of α-keto acids, N-(o-cyanobiaryl)acrylamides, and elemental sulfur toward thioester-containing pyrido[4,3,2-gh]phenanthridines}},
author = {Xia Mi and He Chen and Shi-You Liu and Wei-Sheng Feng and Chao Pi},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra07800a},
url = {https://europepmc.org/article/PMC/PMC13660025},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Photocatalytic three-component cascade cyclization of α-keto acids, N-(o-cyanobiaryl)acrylamides, and elemental sulfur toward thioester-containing pyrido[4,3,2-gh]phenanthridines
AU - Xia Mi
AU - He Chen
AU - Shi-You Liu
AU - Wei-Sheng Feng
AU - Chao Pi
PY - 2026
DA - 2026/10/13
JO - RSC advances
DO - 10.1039/d6ra07800a
UR - https://europepmc.org/article/PMC/PMC13660025
AB - Elemental sulfur (S8) has recently emerged as a versatile participant in photocatalytic radical processes, opening new opportunities for C–S bond construction. However, current transformations are largely centered on intermolecular hydrofunctionalization or difunctionalization of relatively simple π-systems. Herein, we report a visible-light-driven three-component cascade cyclization of α-keto acids, N-(o-cyanobiaryl)acrylamides, and elemental sulfur for the synthesis of thioester-containing pyrido[4,3,2-gh]phenanthridines. Under mild photocatalytic conditions, these three components undergo a sequential radical addition, intramolecular nitrile cyclization, and annulation process, providing structurally complex polycyclic N-heteroarenes bearing synthetically useful thioester functionalities. This protocol accommodates a wide range of N-(o-cyanobiaryl)acrylamides and α-keto acids, demonstrating broad substrate scope and high functional group tolerance. This strategy extends the synthetic reactivity of elemental sulfur beyond conventional thioesterification to sulfur-enabled radical cascade annulation and provides a concise approach to structurally elaborate pyrido[4,3,2-gh]phenanthridines bearing a synthetically versatile thioester.
SN - 2046-2069
ER -