The photobromination of trans-β-styrenesulfonamides in acetic acid at 16–18° C gave about 75: 25 mixtures of threo (cis adducts)-and erythro-1, 2-dibromo-2-arylethane-1-sulfonamides (trans adducts). A similar photobromination of cis-β-styrenesulfonamide afforded a 33: 67 mixture of the threo (trans adduct)-and the erthro-dibromides (cis adduct). The diastereomers could be separated by fractional recrystallization. The cis adducts were ...
