Fragmentation of selected C6H10O isomers: Evidence for a common [C5H7O]+ ion generated by methyl loss from cyclohexene oxide and 5,6-dihydro-4-methyl-2H-pyran

The loss of CH₃˙ from the molecular ions of cyclohexene oxide and 5,6-dihydro-4-methyl-2H-pyran has been investigated. On the basis of metastable peak shape analysis, collision-induced dissociation/mass-analysed ion kinetic energy spectra and thermochemical data it is concluded that the same [C₅H₇O]⁺ ion is formed in both cases.