LAUSR

Abstract Transition mental-catalyzed hydrothiolation of thiol and alkenes, alkynes or dienes is an important method to construct C-S bonds. To understand the control mechanism of the regioselectivity is of great significance in the hydrothiolation of 1,3-dienes which have two unsaturated C=C double bonds for a specific functionalization. In this paper, we explored the regioselective mechanisms of Rh(I)-catalyzed hydrothiolation of 1,3-dienes with different ligands by using density functional theory (DFT) and EDA analysis. The results reveal that the overall catalytic cycle consists of three elementary steps:(i) oxidant addition (ii) Rh-H insertion (iii) C-S reductive elimination. For the cationic catalysts Rh(cod)2SbF6 with JosiPhos ligand, the rate-determining step is Rh-H insertion, in whcih (S)-1,2-Markovnikov addition forming (S)-3a product, is most feasible among the six regio- and enantioselective pathways. The reasons for this phenomenon are steric repulsions and orbital interactions. While for electrically neutral catalysts the rate-determining step turns to be the C-S reductive elimination. The result uncovers that steric repulsions promots 3,4-anti-Markovnikov addition rather than that of 2,1-anti-Markovnikov.