REARRANGEMENT OF AROMATIC SULFONATE ANIONS IN THE GAS-PHASE

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