[en] The NMR method has been used to study the effect of sobstitute electronic properties in reagents on stereoisomerism in arylsulfenchlorides addition to β-deuterostyrenes under the conditions excluding mutual transformation of stereoisomers (kinetic control). Easy transformation of stereoisomers under the conditions usually used for carrying out electpophilic addition reactions is traced. Aryl sulfenchloris des addition to the sUbstituted Z- and epsilon-β - deuterostyrenes, irrespective of the type of the substitutes in the benzene ring of both reagents+ proceeds trans-stereospecifically