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Updated: Aug 6, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Rhodium-Catalyzed [5 + 2] Annulation of Pyrrole Appended BODIPYs: Access to Azepine-Fused BODIPYs
Hui Shu1, Mengjie Guo1, Machongyang Wang1
1Key Laboratory of Chemical Biology and Traditional Chinese Medicine (Ministry of Educational of China), Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, Hunan Normal University, Changsha 410081, China.
Abstract:
Rhodium-catalyzed C-H/N-H [5 + 2] annulations of 8-(pyrrol-2-yl)-appended boron-complexed dipyrromethenes (BODIPYs) with internal alkynes have been established to afford a series of azepine-fused BODIPYs with good yields and excellent regioselectivity, in which the pyrrol-2-yl unit serves as the directing group as a rare example. A RhI intermediate was obtained to indicate a RhI/RhIII catalytic process involved in this reaction. Importantly, the [5 + 2] C-H annulation is demonstrated as a concise strategy to change the optical properties of BODIPY.
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