Metastable decompositions of cyclopentanol ions and [C₅H₁₀O]+˙ ions with the oxygen on the first carbon

Ionized cyclopentanol and [C 5 H 10 O]+˙ ions with the oxygen on the first carbon lose methyl, ethylene, ethyl, ethane and water in their metastable decompositions. We show by collisionally activated decompositions of the products that the losses of ethyl form CH 3 CH 2 CO + , the losses of ethylene form magnified image , and the losses of methyl probably yield magnified image . Deuterium labeling indicates that ethyl loss from ionized cyclopentanol occurs following α‐cleavage of the ring, isomerization to the enol isomer of ionized n ‐pentanal and subsequent isomerization to the 3‐pentanone ion.