Toluidine ions, decomposition

To assert that the decomposition of the Meisenheimer intermediate 2 (step 2) is the rds in the case of o-toluidine requires being more precise, as fliis step is a little more complicated than what has been described in Scheme 33.3. The decomposition of 2 can follow two alternative pathways that are indicated in Scheme 33.4. The first alternative (path a) is a base-catalyzed decomposition process, which consists of the fast deprotonation of intermediate 2 by the amine to form intermediate 3, followed by slow departure of die fluorine ion. The other, is an uncatalyzed decomposition pathway (pafli b) that consists of the initial elimination of fluorine ion leading to aromatic ammonium salt 4, that is subsequently deproto-nated by the base present in die medium in a fast acid-base exchange (Scheme 33.4). 

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