The addition of PhSeCl to α-and β-substituted styrenes in methanol is regio-and stereospecific and affords the products of methoxyselenenylation. These compounds further react with PhSeCl to give the deselenenylation products. In the case of α-substituted styrenes, 1-methoxy, 2-chloroalkanes are produced, whereas with β-substituted styrenes the major reaction products are the 1, 2-dimethoxyalkanes and the 2, 2-dimethoxyalkanes in ...