Methylenecyclopropane Explained

Methylenecyclopropane is an organic compound with the formula . It is a hydrocarbon which, as the name suggests, is derived from the addition of a methylene substituent to a cyclopropane ring. It is a colourless, easily condensed gas that is used as a reagent in organic synthesis.

Synthesis

Methylenecyclopropane can be synthesized via an intramolecular cyclisation reaction from methallyl chloride by treatment with a strong base such sodium amidesodium tert-butoxide (yield 43%)[1] or sodium bis(trimethylsilyl)amide with further treatment by sodium tert-butoxide (yield 72%).[2] Sodium tert-butoxide is used to isomerize byproduct 1-methylcyclopropene into methylenecyclopropane.

Reactions

Being a strained and unsaturated molecule methylenecyclopropane undergoes many reactions, especially in the presence of metal catalysts.[3] For example, methylenecyclopropanes can be converted to cyclobutenes in the presence of a Platinum catalyst.[4] This can be considered similar to the ring expansion seen in vinylcyclopropane rearrangements

Substituted methylenecyclopropanes can also be involved in trimethylenemethane cycloaddition reactions.

See also

References

  1. Salaun, J. R. . Champion, J. . Conia, J. M. . Cyclobutanone from Methylenecyclopropane via Oxaspiropentane . Organic Syntheses . 1977 . 57 . 36 . 10.15227/orgsyn.057.0036.
  2. Binger . Paul . Brinkmann . Axel . Wedemann . Petra . 2002 . Highly Efficient Synthesis of Methylenecyclopropane . Synthesis . en . 10 . 1344–1346 . 10.1055/s-2002-33122 . 0039-7881.
  3. Nakamura, I. . Yamamoto, Y. . Transition Metal-Catalyzed Reactions of Methylenecyclopropanes . Advanced Synthesis and Catalysis . 2002 . 344 . 2 . 111–129 . 10.1002/1615-4169(200202)344:2<111::AID-ADSC111>3.0.CO;2-0 .
  4. PtCl2-Catalyzed Rearrangement of Methylenecyclopropanes Alois Fürstner and Christophe Aïssa J. Am. Chem. Soc.; 2006; 128(19) pp 6306 -6307; Abstract