Premium
Micellar catalysis of organic reactions. Part 36. Nucleophilic aromatic substitution reactions in hydroxy functionalized micelles with bulky head groups
Author(s) -
Broxton Trevor. J.,
Lucas Mathew
Publication year - 1994
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610070809
Subject(s) - chemistry , micelle , nucleophile , hydroxide , medicinal chemistry , aryl , nucleophilic aromatic substitution , reactivity (psychology) , ether , substituent , steric effects , aryl halide , nucleophilic substitution , organic chemistry , photochemistry , catalysis , aqueous solution , alkyl , medicine , alternative medicine , pathology
The reaction of several nitro activated aromatic halides with hydroxide ions was studied in the presence of hydroxy functionalized micelles containing bulky head groups, e.g. C 16 H 33 N + R 2 CH 2 CH 2 OH Br − , where R = Me, Et, Bu. In a biphasic reaction, the aryl halide is first converted into an aryl mincellar ether which subsequently reacts with hydroxide ions to form the phenolic product. Despite the increased nucleophilicity of hydroxide ions as water is squeezed away from the micelle surface by the bulky head groups, no direct reaction of the aromatic substrate with hydroxide ion is detectable. In the second phase of reaction, the breakdown of the aryl micellar ether to form the phenolic product, the order of reactivity in the different micelles is dependent on the steric interactions between substituents ortho to the reaction centre and the head group of the micelle. For compounds having one substituent ortho to the reaction centre, the order of reactivity is Bu > Me > Et, whereas for 2‐chloro‐1,3‐dinitrobenzene, which has two substituents ortho to the reaction centre, the order is Me > Et > Bu.