| Abstract: | Collisionally activated dissociation of deprotonated aromatic sulfonic acids in the gas phase causes rearrangement and fragmentation to produce the corresponding phenoxide ions. The mechanism for this reaction has been investigated and the results of this study favor initial intramolecular nucleophilic addition of a sulfonate oxygen atom to the aromatic ring, a process which is followed by heterolytic cleavage of the carbon–sulfur bond to rearomatize the ring. The product from this addition–elimination sequence is the anion of a sulfurous acid half-ester, which loses SO2 to generate the corresponding phenoxide ion. |
