2-Methylbut-3-yn-2-ol explained

2-Methylbut-3-yn-2-ol is the organic compound with the formula HC₂C(OH)Me₂ (Me = CH₃). A colorless liquid, it is classified as an alkynyl alcohol.

Preparation and use

It arises from the condensation of acetylene and acetone. The addition can be promoted with base^[1] (Favorskii reaction) or with Lewis acid catalysts.^[2] 2-Methylbut-3-yn-2-ol is produced on an industrial scale as a precursor to terpenes and terpenoids.

2-Methylbut-3-yn-2-ol also is used as a monoprotected version of acetylene. For example, after arylation at carbon, the acetone can be removed with base:^[3]

HC₂C(OH)Me₂ + ArX + base → ArC₂C(OH)Me₂ + [Hbase]X

ArC₂C(OH)Me₂ → ArC₂H + OCMe₂In this regard, 2-methylbut-3-yn-2-ol is used similarly to trimethylsilylacetylene.

References

1. Dimethylethynylcarbinol. Donald D. Coffman. Org. Synth.. 1940. 20. 40. 10.15227/orgsyn.020.0040.
2. Facile Enantioselective Synthesis of Propargylic Alcohols by Direct Addition of Terminal Alkynes to Aldehydes. Doug E.. Frantz. Roger. Fässler. Erick M.. Carreira. J. Am. Chem. Soc.. 2000. 122. 8 . 1806–1807. 10.1021/ja993838z.
3. Encyclopedia: 2-Methylbut-3-yn-2-ol. Gordon, John. e-EROS Encyclopedia of Reagents for Organic Synthesis. 2001. 1–2. 10.1002/047084289X.rm157. 0471936235 .