Catalyst leaching as an efficient tool for constructing new catalytic reactions: application to the synthesis of cyclic vinyl sulfides and vinyl selenides

Catalyst leaching from Pd and Ni particles stabilized by organic sulfur and selenium ligands occurs in solution in the presence of phosphanes. This process has been monitored in real time by 1D and 2D NMR spectroscopy and the nature of the metal species established. This catalyst leaching is shown to be a powerful tool for generating new catalytic activity from species formed in situ where the parent bulk particles are inactive. The catalytic system developed has been successfully implemented in a novel synthetic procedure that provides new types of cyclic sulfur and selenium compounds in high yields through the reaction between alkynes and dichalcogenides. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)