2-Methylbut-3-yn-2-ol
Names
Preferred IUPAC name
2-Methylbut-3-yn-2-ol
Other names
  • Ethynylmethylcarbinol
  • Dimethylethynylcarbinol
  • 1,1-Dimethyl-2-propyn-1-ol
  • Dimethylethynylmethanol
  • MB
  • Mebynol
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.003.700 Edit this at Wikidata
EC Number
  • 204-070-5
RTECS number
  • ES0810000
UNII
UN number 1987
  • InChI=1S/C5H8O/c1-4-5(2,3)6/h1,6H,2-3H3
    Key: CEBKHWWANWSNTI-UHFFFAOYSA-N
  • CC(C)(C#C)O
Properties
C5H8O
Molar mass 84.118 g·mol−1
Appearance Colorless liquid
Density 0.8637 g/cm3
Melting point 3 °C (37 °F; 276 K)
Boiling point 104 °C (219 °F; 377 K)
good
Hazards
GHS labelling:
GHS02: FlammableGHS05: CorrosiveGHS07: Exclamation markGHS08: Health hazard
Danger
H225, H226, H302, H315, H318, H319, H335, H361
P201, P202, P210, P233, P240, P241, P242, P243, P261, P264, P270, P271, P280, P281, P301+P312, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P308+P313, P310, P312, P321, P330, P332+P313, P337+P313, P362, P370+P378, P403+P233, P403+P235, P405, P501
Flash point 20 °C (68 °F; 293 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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 is an intermediate in this industrial route to geraniol.[3]

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:[4]

HC2C(OH)Me2 + ArX + base → ArC2C(OH)Me2 + [Hbase]X
ArC2C(OH)Me2 → ArC2H + OCMe2

In this regard, 2-methylbut-3-yn-2-ol is used similarly to trimethylsilylacetylene.

References

  1. ^ Donald D. Coffman (1940). "Dimethylethynylcarbinol". Org. Synth. 20: 40. doi:10.15227/orgsyn.020.0040.
  2. ^ Frantz, Doug E.; Fässler, Roger; Carreira, Erick M. (2000). "Facile Enantioselective Synthesis of Propargylic Alcohols by Direct Addition of Terminal Alkynes to Aldehydes". J. Am. Chem. Soc. 122 (8): 1806-1807. doi:10.1021/ja993838z.
  3. ^ Eberhard Breitmaier (2006). Terpenes: Flavors, Fragrances, Pharmaca, Pheromones. Wiley-VCH. doi:10.1002/9783527609949. ISBN 9783527609949.
  4. ^ Gordon, John (2001). "2-Methylbut-3-yn-2-ol". e-EROS Encyclopedia of Reagents for Organic Synthesis. pp. 1–2. doi:10.1002/047084289X.rm157. ISBN 0471936235.
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