Electrophilic Cyclization of 2-Chalcogenealkynylanisoles: Versatile Access to 2-Chalcogen-benzo[<i>b</i>]furans
                                
                                    
                                        作者:Flávia Manarin、Juliano A. Roehrs、Rafaela Mozzaquatro Gay、Ricardo Brandão、Paulo H. Menezes、Cristina W. Nogueira、Gilson Zeni                                    
                                    
                                        DOI:10.1021/jo802736e
                                    
                                    
                                        日期:2009.3.6
                                    
                                    An efficient synthesis of 2-chalcogen-3-substituted-benzo[b]furan compounds has been accomplished via electrophilic cyclization reaction of 2-chalcogenealkynyl anisoles using I-2, ICl, Br-2 and PhSeBr as electrophile sources. The product distributions were strongly dependent on the nature of substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. The 2-chalcogen-3-iodo-benzo[b]furans obtained smoothly underwent conversion to more complex structures of benzo[b]furan derivatives via palladium- or copper-catalyzed cross-coupling reaction with thiols, diphenyl diselenides, and zincates.