Tellurium Empowered Catalysis for Enantioselective Seleno-Michael Addition Reaction

The development of a new catalyst, which has not been explored before, not only provides an alternative to the existing organocatalysts but also leads to a distinct chemical reactivity. Here, an organotellurium catalyst consisting of a chiral quinine auxiliary displays remarkable activity for the enantioselective delivery of reactive arylselenols as a Michael donor in common solvents such as dichloromethane and acetonitrile. The developed chiral organotellurium-catalyzed arylselenol addition to alkenes shows a broad substrate scope as electron-rich and deficient arylselenols and diversely substituted enones are amenable to the reaction conditions. Control experiments, 77Se, and 125Te NMR, suggest that non-bonded Te...Se interaction between catalyst and arylselenol seems responsible for accelerated and highly enantioselective delivery of arylselenol to enone. The practically synthesized chiral organoselenides have also been readily post-derivatized by taking advantage of the leaving group ability and recyclability of arylselenium.