green procedure for the synthesis of Markovnikov i.e. branched vinyl sulfides in aqueous media was developed by employing the dinuclear Rh(I) complexes of hydrophilic phosphines as catalysts in the alkyne hydrothiolation with aliphatic thiols. Deuterium-labeling studies provide evidence for the aptness of these dinuclear catalysts to form selectively the Markovnikov syn-addition products. Catalyst order