Alkyne zipper reaction

The alkyne zipper reaction is an organic reaction which isomerizes an organic compound containing an internal alkyne into a terminal alkyne. This was first reported by Charles Allen Brown and Ayako Yamashita in 1975.[1] The isomerization reaction proceeds for straight-chain alkynes and acetylinic alcohols and provides a useful approach for remote functionalization in long-chain hydrocarbons.[2]

The reaction requires a strong base. The base used by Brown and Yamashita was potassium 1,3-diaminopropanide, generated in situ by adding potassium hydride to the solvent 1,3-diaminopropane.[1] Alternative approaches have been investigated due to the expensive and hazardous nature of potassium hydride; ethylenediamine has been found to be an unsuitable replacement for 1,3-diaminopropane. As an example, for the synthesis of 9-decyn-1-ol from 2-decyn-1-ol, the lithium salt of 1,3-diaminopropane in the presence of potassium tert-butoxide affords yields of approximately 85%.[2]

HO–CH2C≡C–(CH2)6CH3 → HO(CH2)8–C≡CH

References

  1. ↑ 1.0 1.1 C. A. Brown and A. Yamashita (1975). "Saline hydrides and superbases in organic reactions. IX. Acetylene zipper. Exceptionally facile contrathermodynamic multipositional isomeriazation of alkynes with potassium 3-aminopropylamide". J. Am. Chem. Soc. 97 (4): 891–892. doi:10.1021/ja00837a034.
  2. ↑ 2.0 2.1 Suzanne R. Abrams and Angela C. Shaw (1988). "Triple Bond Isomerizations: 2- to 9-decyn-1-ol". Org. Synth. 66: 127.; Coll. Vol. 8, p. 146