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Updated: Jul 15, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Photocatalytic Conversion of Aminocyclopropanes to γ-Lactams by Sequential Ring-Expansion and Peripheral
Feng-Shuo Bao1, Guo-Qing Li1, Yu Qian1
1College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei430079, China.
Abstract:
Rings underpin pharmaceuticals, agrochemicals, and materials, driving renewed interest in skeletal ring expansion. Current skeletal ring expansion strategies mainly focus on single-atom insertion or rearrangement; reliable methods for multiple single-atom insertion and peripheral diversification of saturated small rings are lacking. Herein, we report a general and efficient photocatalytic system directly converting aminocyclopropanes to γ-lactams via sequential C-/N-single-atom [n + 2] ring-expansion and peripheral diversification. The system accomplishes both γ-lactam formation and subsequent diversification at the γ-position via six distinct bond-forming reactions across hundreds of synthetic examples under predictable reaction conditions. Experimental and computational studies converge on photoredox-mediated radical pathways.
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