Chemoselective Quinoline and Isoquinoline Reduction by Energy Transfer Catalysis Enabled Hydrogen Atom Transfer

• Published in: Angewandte Chemie International Edition Vol. 62; no. 48; pp. e202312203 - n/a
• Main Authors: Liu, De‐Hai, Nagashima, Kyogo, Liang, Hui, Yue, Xue‐Lin, Chu, Yun‐Peng, Chen, Shuming, Ma, Jiajia
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 27.11.2023; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Alkanes; Alkenes; Catalysis; Chemical reduction; Chemistry; Chemistry, Multidisciplinary; Chemoselectivity; Dearomatization; Energy Transfer; Functional groups; Hydrogen; Hydrogen atoms; Physical Sciences; Quinoline; Reduction; Science & Technology; Visible Light; ELECTROREDUCTION; Chemoselectivity; ARENES; PHOTO-BIRCH REDUCTION; AROMATIC-COMPOUNDS; SODIUM-BOROHYDRIDE; Reduction; Visible Light; PHOTOREDUCTION; Dearomatization; Energy Transfer; LITHIUM; ELECTRON-TRANSFER REACTIONS; ACCESS
• DOI: 10.1002/anie.202312203
• ISSN: 1433-7851; 1521-3773

(Hetero)arene reduction is one of the key avenues for synthesizing related cyclic alkenes and alkanes. While catalytic hydrogenation and Birch reduction are the two broadly utilized approaches for (hetero)arene reduction across academia and industry over the last century, both methods have encountered significant chemoselectivity challenges. We hereby introduce a highly chemoselective quinoline and isoquinoline reduction protocol operating through selective energy transfer (EnT) catalysis, which enables subsequent hydrogen atom transfer (HAT). The design of this protocol bypasses the conventional metric of reduction reaction, that is, the reductive potential, and instead relies on the triplet energies of the chemical moieties and the kinetic barriers of energy and hydrogen atom transfer events. Many reducing labile functional groups, which were incompatible with previous (hetero)arene reduction reactions, are retained in this reaction. We anticipate that this protocol will trigger the further advancement of chemoselective arene reduction and enable the current arene‐rich drug space to escape from flatland. An alkene and a (hetero)arene, to be reduced or retained? In contrast to conventional processes, in the reported hydrogen atom transfer (HAT) protocol enabled by energy transfer (EnT) catalysis, the benzenoid ring of a quinoline is more easily reduced than an electron‐deficient alkene. Furthermore, many reducing labile moieties, such as aryl iodides, electron‐deficient alkynes, benzsulfamides, and benzyl ethers, are compatible with this method.