Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols
作者:Masahito Yoshida、Yuta Fujino、Koya Saito、Takayuki Doi
DOI:10.1016/j.tet.2011.09.063
日期:2011.12
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 cyclizedauronederivatives. Utilizing this method, methoxy substituted flavone and alkyl substituted γ-benzopyranone derivatives were synthesized.
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.
Pd-Catalyzed Isocyanide Assisted Reductive Cyclization of 1-(2-Hydroxyphenyl)-propargyl Alcohols for 2-Alkyl/Benzyl Benzofurans and Their Useful Oxidative Derivatization
An unusual Pd-catalyzed isocyanide assisted 5exo-dig reductive cyclization of 1-(2-hydroxyphenyl)-propargyl alcohols is achieved for 2-alkyl/benzyl benzofurans. The reaction features a high substrate scope, insensitivity to air, and excellent product yielding. Further, a direct metal-free C-H functionalization (azidation, alkoxylation, and hydroxylation) and selective oxidative cleavage of thus synthesized 2-benzylfurans are described for azido-, alkoxy-, hydroxyl-, amide-, and tetrazolyl adducts.