Methylenecyclopropane
Organic compound, (CH2)2C=CH2
From Wikipedia, the free encyclopedia
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.
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| Names | |
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| Preferred IUPAC name
Methylidenecyclopropane | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.025.584 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C4H6 | |
| Molar mass | 54.092 g·mol−1 |
| 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).
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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.