1: With lithium boron tetrafluoride; [Ru(2,2′-bipyridine)3][hexafluorophosphate]2; 2,3,5,6-tetramethyl-p-benzoquinone in aceonitrile T=20°C; 5 h; Inert atmosphereIrradiationMolecular sieve; 2: With water; ammonium chloride in acetonitrile T=20°C; 1 h; Inert atmosphereMolecular sieve; optical yield given as percent de;

(i), (ii) H2O; Multistep reaction;