Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad, 500607, Telangana, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
Chemistry. 2023 May 16;29(28):e202203354. doi: 10.1002/chem.202203354. Epub 2023 Apr 4.
Herein, fullerene (C ) is introduced as an effective photoredox catalyst for the construction of a highly functionalised pyrrolo[2,1-a]isoquinoline framework by 1,3-dipolar cycloaddition-aromatisation reaction sequence. The ability of C to efficiently harvest visible light, its long-triplet state lifetime, good photostability, and strong singlet oxygen generation potential (Φ ≈1), make it an efficient photoredox catalyst. Upon photoirradiation, C promotes the formation of singlet oxygen and superoxide radical by energy transfer (EnT) and single electron transfer (SET) mechanism. The superoxide radical acts as a potential oxidant in the formation of azomethine ylide through the oxidation-deprotonation tandem process. Azomethine ylide further participates in [3+2]-cycloaddition reaction protocol with alkene/alkyne to give the corresponding pyrrolo[2,1-a]isoquinolines. Interestingly, this protocol allows the activation of a wide range of substrates giving access to a diverse library of 48 well-decorated pyrrolo[2,1-a]isoquinolines with good functional group tolerance.
在这里，富勒烯（C ）被引入作为一种有效的光氧化还原催化剂，通过 1,3-偶极环加成-芳构化反应序列构建高度官能化的吡咯并[2,1-a]异喹啉骨架。C 能够有效地收集可见光，具有长三重态寿命、良好的光稳定性和强的单线态氧生成能力（Φ≈1），使其成为一种有效的光氧化还原催化剂。光照射下，C 通过能量转移（EnT）和单电子转移（SET）机制促进单线态氧和超氧自由基的形成。超氧自由基通过氧化-去质子化串联过程作为形成亚胺叶立德的潜在氧化剂。亚胺叶立德进一步与烯烃/炔烃参与[3+2]-环加成反应，得到相应的吡咯并[2,1-a]异喹啉。有趣的是，该方案允许广泛的底物的活化，从而获得具有良好官能团耐受性的 48 种结构多样的经过良好修饰的吡咯并[2,1-a]异喹啉文库。
