Methylcyclopropane

Methylcyclopropane (C4H8) is the alkyl cycloalkane compound of methane and cyclopropane.

Usage
It is used as functional group in tertiary amines.

Reactions
Methylcyclopropane provides an extreme example of the general decrease in the stability of alkyl cycloalkanes with decreasing ring size, due to the Baeyer tension. They react in a similar way to alkenes, although they don't react with the EA (cf. electrophilic addition), but with the SN2 (cf. nucleophilic substitution) reaction mechanism. These reactions are both ring opening reactions and bond cleavage reactions outside the ring. Two examples are the halogenation reactions


 * H3C-CycProp + HBr → H3C-CHBr-CH2-CH3 (ring opening)


 * H3C-CycProp + HBr → H3C-H + Br-CycProp (bond cleavage)

The latter reaction is important due to cleavage of the cyclopropyl ring in tertiary amines.