Synthesis of γ-benzopyranone by TfOH-promoted regioselective cyclization of o-alkynoylphenols
Regioselective cyclization of o-alkynoylphenols forming γ-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 γ-benzopyranones in high yields.
Yoshida, Masahito,Fujino, Yuta,Doi, Takayuki
supporting information; experimental part
p. 4526 - 4529
(2011/10/09)
Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols
A catalytic amount of DMAP promoted cyclization of o-alkynoylphenols via a 6-endo cyclization mode leading to flavone derivatives in high yields without forming 5-exo cyclized aurone derivatives. Utilizing this method, methoxy substituted flavone and alkyl substituted γ-benzopyranone derivatives were synthesized.