Remarkable ligand effect in Ni- and Pd-catalyzed bisthiolation and bisselenation of terminal alkynes: Solving the problem of stereoselective dialkyldichalcogenide addition to the C C bond

We have developed two new catalytic systems based on Ni and Pd complexes to solve the challenging problem of dialkyldichalcogenide (Alk(2)E(2); E = S, Se) addition to alkynes. A comparative study of two catalytic systems-Ni/PMe2Ph and Pd/PCy2Ph-has revealed that the Ni catalyst is superior with respect to high catalytic activity and more general scope relative to the Pd system. A novel synthetic methodology was developed for the preparation of (Z)-bis(alkylthio)alkenes and (Z)-bis(alkylseleno)alkenes from terminal alkynes with excellent stereoselectivity and high yields.