Alkynes are useful reagents as well as products in organic synthesis. They can be synthesized from low-cost, readily available alcohols. However, these processes usually require two steps: the alcohols are first oxidized to aldehydes or ketones, which are then converted to alkynes.

Hua-Li Qin, Wuhan University of Technology, China, and colleagues have developed a direct synthesis of alkynes from alcohols, using a dehydration and dehydrogenation process which is mediated by sulfuryl fluoride (SO₂F₂). The team used SO₂F₂ to activate dimethyl sulfoxide (DMSO) for alcohol oxidation. The resulting carbonyl intermediates further react with SO₂F₂ in situ to give vinyl fluorosulfates. K₂CO₃ and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were used as bases. CsF was used to promote the final step, the elimination of a fluorosulfonic ester. DMSO also serves a the solvent for the reaction.

The desired alkynes were obtained in high yields and with sufficient purity for further functionalization in one-pot reactions. The reaction protocol works well for a variety of homobenzylic and aliphatic alcohols. The reagents are readily available at low costs and the reaction proceeds under mild conditions.

• SO₂F₂-Mediated Oxidative Dehydrogenation and Dehydration of Alcohols to Alkynes,
  Gao-Feng Zha, Wan-Yin Fang, You-Gui Li, Jing Leng, Xing Chen, Hua-Li Qin,
  J. Am. Chem. Soc. 2018.
  https://doi.org/10.1021/jacs.8b10069