Synthesis of γ-Benzopyranone by TfOH-Promoted Regioselective Cyclization of <i>o</i>-Alkynoylphenols
                                
                                    
                                        作者:Masahito Yoshida、Yuta Fujino、Takayuki Doi                                    
                                    
                                        DOI:10.1021/ol2016934
                                    
                                    
                                        日期:2011.9.2
                                    
                                    Regioselective cyclization of o-alkynoylphenols forming gamma-benzopyranones has been demonstrated. Trifluoromethanesulfonic acid (TfOH) induced 6-endo cyclization of o-alkynoylphenols without forming 5-exo cyclized benzofuranone derivatives to provide the corresponding gamma-benzopyranones in high yields.