10.1021/ol2016934.s001 Masahito Yoshida Masahito Yoshida Yuta Fujino Yuta Fujino Takayuki Doi Takayuki Doi Synthesis of γ-Benzopyranone by TfOH-Promoted Regioselective Cyclization of <i>o</i>-Alkynoylphenols American Chemical Society 2011 Regioselective cyclized Cyclization TfOH Benzopyranone benzofuranone cyclization benzopyranone derivative Synthesi endo exo yield Trifluoromethanesulfonic acid 2011-09-02 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Synthesis_of_Benzopyranone_by_TfOH_Promoted_Regioselective_Cyclization_of_i_o_i_Alkynoylphenols/2618263 Regioselective cyclization of <i>o</i>-alkynoylphenols forming γ-benzopyranones has been demonstrated. Trifluoromethanesulfonic acid (TfOH) induced 6-<i>endo</i> cyclization of <i>o</i>-alkynoylphenols without forming 5-<i>exo</i> cyclized benzofuranone derivatives to provide the corresponding γ-benzopyranones in high yields.