Photopromoted Entry to Benzothiophenes, Benzoselenophenes, 3<i>H</i>-Indoles, Isocoumarins, Benzosultams, and (Thio)flavones by Gold-Catalyzed Arylative Heterocyclization of Alkynes
作者:Benito Alcaide、Pedro Almendros、Eduardo Busto、Fernando Herrera、Carlos Lázaro-Milla、Amparo Luna
DOI:10.1002/adsc.201700427
日期:2017.8.7
gold‐photoredox‐catalyzed reactions of heteroatom (N, S, Se, O) tethered alkynes with arenediazonium salts selectively proceeded to build vicinal diaryl‐substituted 2H‐benzo[e][1,2]thiazine 1,1‐dioxides (benzosultams), benzoselenophenes, benzothiophenes, 4H‐chromen‐4‐ones (flavones), 3H‐indoles, 1H‐isochromen‐1‐ones (isocoumarins), and 4H‐thiochromen‐4‐ones (thioflavones). Moreover, the utility of functionalized
An unexpected palladium‐catalyzed carbonylative synthesis of 2,3‐disubstituted chromones has been developed. Starting from 2‐bromofluorobenzenes and ketones, the corresponding chromones were produced in good yields. By control experiments, this transformation was found to proceed through a sequential carbonylation/Claisen–Hasse rearrangement/intramolecular nucleophilic aromatic substitution approach