Halonium Ion-Assisted Deiodination of Styrene-Based Vicinal Iodohydrins Followed by Rearrangement through Phenyl Migration

Acid activation of bromate/bromide couple at 0−10 °C was found to trigger the deiodination of styrene-based vicinal iodohydrins. Violet coloration of the organic layer was ascribed to formation of IBr. Deiodination was followed by phenyl migration and deprotonation leading to formation of phenyl acetone and 2-phenylpropanal in good yields from 1-iodo-2-phenylpropan-2-ol and 2-iodo-1-phenylpropan-1-ol, respectively. Phenyl acetaldehyde−which was obtained in 92% GC yield from styrene iodohydrin−was also presumably formed in analogous manner. NBS and HOCl too were effective for transformation of styrene iodohydrin into phenyl acetaldehyde.