An Efficient Synthesis of Aurone Derivatives by the Tributylphosphine-catalyzed Regioselective Cyclization of o-Alkynoylphenols

An organocatalytic regioselective synthesis of aurones from o-alkynoylphenols was achieved. A catalytic amount of tributylphosphine selectively induced the 5-exo cyclization of o-alkynoylphenols under ambient conditions leading to aurone derivatives in high to excellent yields.