Synthesis of Highly Enantioenriched Propelladienes and their Application as Ligands in Asymmetric Rh-Catalyzed 1,4-Additions

The first synthesis of highly enantioenriched [4.3.3]propelladienes is reported. The novel bridged bicyclo[3.3.0] dienes were applied as steering ligands in the rhodium-catalyzed asymmetric arylation of cyclic enones. The catalytic system showed high catalytic activity, and the 1,4-adducts were obtained in good to excellent yields (46-99%) with enantioselectivities up to 96% ee.