MICELLAR CATALYSIS OF ORGANIC-REACTIONS .29. SNAR REACTIONS WITH NEUTRAL NUCLEOPHILES

The reaction of a number of nitroactivated halobenzoates (1-4) with some primary and tertiary amines has been studied in the presence of micelles of cetyltrimethylammonium bromide (CTAB) and in water. With primary amines aminodehalogenation was observed, and it was found that if the reaction center of the aromatic substrate was located at the micelle water interface (compounds 1 and 2) the reaction was catalyzed by CTAB, but if the reaction center was more deeply buried into the micellar interior the reaction with aniline was inhibited by micelles of CTAB (compounds 3 and 4), while CTAB had little effect on the reaction of n-propylamine with compound 4. With the more sterically bulky tertiary amines, hydroxydehalogenation was observed rather than amino-dehalogenation, and the reactions were all catalyzed by CTAB, but for the substrate with a more deeply buried reaction center (compound 4), the catalysis was stronger than for that with a reaction center at or near the interface (compound 2). The mechanism of hydroxydehalogenation was found to be specific base catalysis by the tertiary amine. Thus the observation of micellar catalysis or inhibition of these reactions depends on the orientation of the organic substrate within the micellar aggregate and the reaction product, amine or phenol, depends on the steric bulk of the amine at least for the compounds investigated here which contain two substitutents ortho to the reaction center.