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Radical‐Cation Cascade to Aryltetralin Cyclic Ether Lignans Under Visible‐Light Photoredox Catalysis
Author(s) -
Xiang JiaChen,
Wang Qian,
Zhu Jieping
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202007548
Subject(s) - chemistry , ether , stereocenter , alkene , radical ion , diene , lactone , catalysis , photochemistry , organic chemistry , stereochemistry , medicinal chemistry , enantioselective synthesis , ion , natural rubber
The development of concise, sustainable, and cost‐effective synthesis of aryltetralin lignans, bearing either a fused lactone or cyclic ether, is of significant medicinal importance. Reported is that in the presence of Fukuzumi's acridinium salt under blue LED irradiation, functionalized dicinnamyl ether derivatives are converted into aryltetralin cyclic ether lignans with concurrent generation of three stereocenters in good to high yields with up to 20:1 diastereoselectivity. Oxidation of an alkene to the radical cation is key to the success of this formal Diels–Alder reaction of electronically mismatched diene and dienophile. Applying this methodology, six natural products, aglacin B, aglacin C, sulabiroin A, sulabiroin B, gaultherin C, and isoshonanin, are synthesized in only two to three steps from readily available biomass‐derived monolignols. A revised structure is proposed for gaultherin C.