Some of the applications of 3-butynoic acid are: · Synthesis of functionalized γ-butyrolactones and tetrahydrofurans via Conia-ene cyclizations. · Synthesis of allenoates for [2+2] cycloadditions with alkenes. · Phosphine-catalyzed synthesis of highly functionalized coumarins. · Synthesis of various useful organotin reagents via radical hydrostannation of 3-butynoic acid. Some of the applications of 3-butynoic acid are: · Synthesis of functionalized γ-butyrolactones and tetrahydrofurans via Conia-ene cyclizations. · Synthesis of allenoates for [2+2] cycloadditions with alkenes. · Phosphine-catalyzed synthesis of highly functionalized coumarins. · Synthesis of various useful organotin reagents via radical hydrostannation of 3-butynoic acid.