Competitive photochemical brominolyses of substituted phenylcyclopropanes in carbon disulfide at 20" C gave linear Hammett plots with CT+(p=-1.84, correlation coefficient-0.996) or with u (p=-2.16, correlation coefficient-0.982). The substituent effect is similar to that found in homolytic bromination of toluenes, and is similarly interpreted in terms of a polar transition state for the displacement reaction.
