COMPARATIVE-STUDY OF PHOTOAMIDATION OF A MIXED OLEFIN RFCH=CHRH IN HOMOGENEOUS AND MICROSCOPICALLY HETEROGENEOUS MEDIA

Photoamidation by formamide of the olefin C8F17CH=CHC10h21 was carried out in two types of reaction media: (1) a homogeneous medium, tert-butyl alcohol, and (2) a microscopically heterogeneous medium represented by a nonaqueous microemulsion in which water is replaced by formamide. The olefin and the formamide are both reactants and constituents of the microemulsions. In tert-butyl alcohol, amidation occurred preferentially at the a position on the alkyl chain, whereas in the microemulsions, the opposite regioselectivity was observed, with the carbamoyl radical attacking the a position of the fluoroalkyl chain. Differences in regioselectivity in the different media are interpreted in terms of polar and steric effects. In tert-butyl alcohol, the reaction appeared to be governed by steric effects, while in the microemulsions, polar effects were more important. © 1990, American Chemical Society. All rights reserved.