Radical-Mediated 1,2-Formyl/Carbonyl Functionalization of Alkenes and Application to the Construction of Medium-Sized Rings

• Published in: Angewandte Chemie International Edition Vol. 55; no. 48; pp. 15100 - 15104
• Main Authors: Li, Zhong-Liang, Li, Xiao-Hua, Wang, Na, Yang, Ning-Yuan, Liu, Xin-Yuan
• Format: Journal Article
• Language: English
• Published: WEINHEIM Blackwell Publishing Ltd 21.11.2016; Wiley; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Aldehydes; Alkenes; Carbonyl compounds; Chemistry; Chemistry, Multidisciplinary; heterocycles; medium-ring systems; Physical Sciences; radicals; Science & Technology; synthetic methods; ORGANIC-SYNTHESIS; radicals; HYDROGEN-ATOM TRANSFER; CARBON RADICALS; alkenes; C-H FUNCTIONALIZATION; OXIDATIVE TRIFLUOROMETHYLATION; TRIFLUOROMETHYLTHIOLATION REACTIONS; FRAGMENTATION REACTIONS; medium-ring systems; heterocycles; BETA-FRAGMENTATION; LIGHT PHOTOREDOX CATALYSIS; synthetic methods; CYCLIZATION
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201608198

A novel radical 1,2‐formylfunctionalization of alkenes involving 1,2(4,5)‐formyl migration triggered by addition of various carbon‐ and heteroatom‐centered radicals to alkenes has been developed for the first time, thus providing straightforward access to diverse β‐functionalized aldehydes with good efficiency, remarkable selectivity, and excellent functional group tolerance. Analogous transformations mediated by a keto‐carbonyl migration have also been effected under similar conditions. This method was used to access ring systems including various benzannulated nine‐, ten‐, and eleven‐membered rings, complex 6‐5(6,7)‐6(5) fused rings, and bridged rings with diverse functionalities. The old 1,2: A novel 1,2‐formyl functionalization of unactivated alkenes involving formyl migration and addition of radicals to alkenes has been developed for access to synthetically important β‐functionalized aldehydes. The analogous keto‐carbonyl migration has been performed to synthesize challenging medium‐sized diketones, which were additionally transformed into complex fused rings.