Palladium-catalyzed asymmetric allylic substitution reactions using new chiral phosphinooxathiane ligands.

The development of the new chiral ligands for use in asymmetric catalytic reactions has drawn considerable interest in the last 10 years. In this area, palladiumcatalyzed allylic substitution reactions have been shown to be effective tools for the construction of carbon-carbon and carbon-heteroatom bond1 formation, and several efficient enantioselective catalysts such as C2and C1symmetric bidentate chiral ligands1b and non-C2-symmetric2 ligands such as phosphineoxazoline3 have been explored for these reactions. Oxathianes,4 however, have not been studied extensively as chiral ligands, and to the best of our knowledge, they have been used only in asymmetric carbonyl epoxidations.5 In this paper, we report the synthesis of novel norbornane-based phos-