Propiolic acid

4-Hydroxy diphenyl ketone, propargyl bromide and tetrabutyl ammonium bromide were purchased from HEOWNS (Tianjin, China). Sodium azide, CuSO₄·5H₂O, and pyridine were purchased from Tianjin Chemical Regents (Tianjin, China). Tetrahydrofuran (THF), dimethylsulfoxide (DMSO), toluene, and dichloromethane were purchased from JiangTian chemical reagents (Tianjin, China). Ascorbic acid sodium salt, N,N-Dicyclohexylcarbodiimide, propiolic acid, and 3-aminopropyltriethoxysilane were provided by Energy-Chemical (Shanghai, China). Kromasil spherical silica gel (5 μm, 100 Å) was purchased from Eka Chemicals (Bohus, Sweden). Mono-6A-deoxy-(p-tosylsufonyl)-β-cyclodextrin (TsO-CD) and alkynl modified silica was synthesized according to the reported procedure. THF and toluene were distilled over Na/benzophenone prior to use. Other chemicals were of analytical grade and used without further purification. The metal salts used for study were PbCl₂, ZnCl₂, CoCl₂, FeCl₃, MgCl₂, CaCl₂, KCl, CuCl₂, CdCl₂, NaCl, NH₄Cl, Al(NO₃)₃, and AgNO₃. Deionized (DI) water was used in the experiments.

Methyl propiolate (MP, >98.0%), methyl ethynyl ketone (MEK, >97.0%), 1,4-diazabicyclo[2.2.2]octane (DABCO, >98.0%), and trimethylolpropane (>98.0%) were purchased from Tokyo Chemical Industry Co, Ltd. Heavy water (D₂O, 99.9 atom% D) and heavy oxygen water (H₂¹⁸O, 98 atom % ¹⁸O), and propiolic acid (98%) were purchased from Energy Chemical. THF (inhibitor-free, HPLC grade, ≥99.9%) and DCM (HPLC grade, ≥99.9%) were purchased from Sigma-Aldrich. Water was purified with a Millipore filtration system.