Methylenecyclopropane

Methylenecyclopropane is an organic compound with the formula (CH₂)₂C=CH₂. It is a hydrocarbon which, as the name suggests, is derived from the addition of a methylene (=CH₂) substituent to a cyclopropane ring. It is a colourless, easily condensed gas that is used as a reagent in organic synthesis.

Methylenecyclopropane

Names
Preferred IUPAC name Methylidenecyclopropane
Identifiers
CAS Number	6142-73-0
3D model (JSmol)	Interactive image
ChemSpider	72487
ECHA InfoCard	100.025.584
PubChem CID	80245
UNII	NC8LG5TD4N Y
CompTox Dashboard (EPA)	DTXSID20210361
InChI InChI=1S/C4H6/c1-4-2-3-4/h1-3H2 Key: XSGHLZBESSREDT-UHFFFAOYSA-N InChI=1/C4H6/c1-4-2-3-4/h1-3H2 Key: XSGHLZBESSREDT-UHFFFAOYAB
SMILES C=C1CC1
Properties
Chemical formula	C4H6
Molar mass	54.09
Density	0.8 g/cm3
Boiling point	9 to 12 °C (48 to 54 °F; 282 to 285 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Methylenecyclopropane can be synthesized via an intramolecular cyclisation reaction from methallyl chloride by treatment with a strong base such sodium amide—sodium 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

• Methylenecyclopropene
• 1-Methylcyclopropene
• Methylcyclopropane
• Cyclopropene