Chiral Phosphine Oxide–Sc(OTf)₃ Complex Catalyzed Enantioselective Bromoaminocyclization of 2‑Benzofuranylmethyl N‑Tosylcarbamates. Approach to a Novel Class of Optically Active Spiro Compounds

An efficient enantioselective bromoaminocyclization of 2-benzofuranylmethyl N-tosylcarbamates catalyzed by a chiral phosphine oxide–Sc­(OTf)₃ complex is described. A wide variety of optically active spiro benzofuran oxazolidinones can be obtained with high enantioselectivities.