MICELLAR CATALYSIS OF ORGANIC-REACTIONS .36. NUCLEOPHILIC AROMATIC-SUBSTITUTION REACTIONS IN HYDROXY FUNCTIONALIZED MICELLES WITH BULKY HEAD GROUPS

The reaction of several nitro activated aromatic halides with hydroxid e ions was studied in the presence of hydroxy functionalized micelles containing bulky head groups, e.g. C(16)H(33)N(+)R(2)CH2CH2OH Br-, whe re R = Me, Et, Bu. In a biphasic reaction, the aryl halide is first co nverted into an aryl mincellar ether which subsequently reacts with hy droxide ions to form the phenolic product. Despite the increased nucle ophilicity of hydroxide ions as water is squeezed away from the micell e surface by the bulky head groups, no direct reaction of the aromatic substrate with hydroxide ion is detectable. In the second phase of re action, the breakdown of the aryl micellar ether to form the phenolic product, the order of reactivity in the different micelles is dependen t on the steric interactions between substituents ortho to the reactio n centre and the head group of the micelle. For compounds having one s ubstituent ortho to the reaction centre, the order of reactivity is Bu > Me > Et, whereas for 2-chloro-1,3-dinitrobenzene, which has two sub stituents ortho to the reaction centre, the order is Me > Et > Bu.