Mechanistic study of palladium catalyzed S-S and Se-Se bonds addition to alkynes

The mechanistic study of palladium catalyzed S � /S and Se � /Se bonds addition to alkynes revealed the involvement of dinuclear transition metal complexes in the catalytic cycle. Coordination of alkyne to dinuclear transition metal complex was found to be the rate determining step of the reaction. An unusual phosphine ligand effect increasing the yield of addition reaction was found in the studied system. A new synthetic procedure was developed to perform the catalytic reaction using easily available Pd(II) complex. The scope of the reaction and the reactivity of S � /S and Se � /Se bonds toward alkynes were investigated. The X-ray structure of the product of S � /S bond addition reaction showed favorable geometry for the possible application as a chelate ligand. # 2003 Elsevier B.V. All rights reserved.