Abstract
A number of reactions in which "positive" bromine is an intermediate reagent have been investigated and optically active compounds have been used in order to study the mechanisms of some of these reactions. The preparation and resolution of 2-ethylhexanaic and alpha-phenylpropionic acids and the preparation of alpha-(p-nitro-phenyl)-propionic acid are described. The reactions of the silver salts of these acids with two equivalents of bromine have been investigated; from optically active silver 2-ethyl-hexanoate specimens of optically active 3-bromoheptane were obtained. A reaction mechanism in accord with this result is proposed. Attempts to effect an asymmetric synthesis by the addition of (+)- and (-)-2-ethylhexanoyl hypobromite to styrene. followed by alkaline hydrolysis, yielded optically inactive phenyl glycol. The bromine cation, formed by the addition of silver nitrate to acidic solutions of bromine, effected substitution in the phenyl nucleus of alpha-phenylpropionic acid. When bromine cations were allowed to react in the presence of acetate iom with styrene and cyclo-hexene. the quantities of the corresponding bromo-acetates which were formed were substantially greater, and the quantities of the dibromides less, than those formed in parallel experiments in which bromide ions were not removed.