928-90-5

Clear pale yellow liquid

5-Hexyn-1-ol is used as starting material for the preparation of terminal alkynes and lactones containing terminal alykyne groups. It is also used in the synthesis of cinnoline-fused cyclic enediyne, llycopodium alkaloids, (+)-nankakurine A and (+)-nankakurine B and 7-benzoyloxy-3-(2-nitrophenylseleno)-1,5-cyclodecadiyne.

General procedure for the synthesis of 5-hexyn-1-ol from 2-(chloromethyl)tetrahydro-2H-pyran: A small amount of iron(III) nitrate hydrate IX was added as a catalyst to about 100 mL of liquid ammonia at -40 °C. Subsequently, sodium metal (85.3 g, 3.72 mol) was added in small portions. After confirming the formation of sodium amide by observing the change in color of the reaction mixture from dark blue to gray, the reaction was slowly added dropwise, which lasted for 5 hours, after which the reaction mixture was continued to be stirred for 3 hours. Upon completion of the reaction, the cold bath was removed and nitrogen was introduced to accelerate the evaporation of ammonia. Once the ammonia had largely evaporated, water was added slowly and dropwise at ambient temperature to quench the reaction. The reaction mixture was extracted with ether, all organic layers were combined and dried with anhydrous magnesium sulfate. The dried organic phase was filtered, the filtrate was concentrated under reduced pressure to remove the solvent, and the residue was purified by vacuum distillation to give 53.8 g (67% yield) of the target product 5-hexyn-1-ol as a colorless oil.

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