Phenanthrene Synthesis by Eosin Y-Catalyzed, Visible Light- Induced [4+2] Benzannulation of Biaryldiazonium Salts with Alkynes
作者:Tiebo Xiao、Xichang Dong、Yanchi Tang、Lei Zhou
DOI:10.1002/adsc.201200569
日期:2012.11.26
A metal-free, visible light-induced [4+2] benzannulation of biaryldiazonium salts with alkynes was developed. With eosin Y as photoredox catalyst, a variety of 9-substituted or 9,10-disubstitutedphenanthrenes were obtained via a cascade radical addition and cyclization sequence.
A rhodium-catalyzedannulative coupling of (2-arylphenyl)boronic acids with alkynes has been developed for the facile construction of phenanthrene frameworks. The reaction proceeded without external bases, and dioxygen worked as a terminal oxidant. Deuterium-labeling experiments indicated the involvement of five-membered rhodacycle intermediates.
Extended Study of Visible-Light-Induced Photocatalytic [4 + 2] Benzannulation: Synthesis of Polycyclic (Hetero)Aromatics
作者:Tanmay Chatterjee、Da Seul Lee、Eun Jin Cho
DOI:10.1021/acs.joc.7b00413
日期:2017.4.21
extended study of [4 + 2] benzannulation reactions of 2-(hetero)aryl-substituted anilines with alkynes by visible light photocatalysis. The method requires the use of tBuONO as a diazotizing agent and 0.3 mol % of fac-Ir(ppy)3 as a photocatalyst at room temperature. The reaction proceeded in a chemo- and regioselective manner with high functionalgroup tolerance under mild conditions allowing the preparation