Hydrothiolation of alkynes with thiol-catechol derivatives catalysed by CuNPs/TiO: exploring the reaction mechanism by DFT calculations.

Density functional theory (DFT) calculations were applied to describe the hydrothiolation reaction of activated alkynes with thiols bearing a catechol group. The thiol-yne click (TYC) process was efficiently catalysed by a CuNPs/TiO nanocatalyst giving the corresponding -Markovnikov vinyl sulphides with high -stereoselectivity. Based on the experimental results and DFT studies, a plausible reaction mechanism is proposed, which implies the activation of the carbon-carbon triple bond by coordination to the copper centre, followed by a stereoselective (external) nucleophilic attack to give preferentially the -vinyl sulphide isomer. Additionally, experimental and theoretical studies strongly correlate with the proposed synergistic role for the TiO support in the catalytic process.