N-chloro-succinimide in acetonitrile T=20°C; 3 h;

in tetrahydrofuran 0.166667 h; Inert atmosphereSealed tube;

tert.-butylhydroperoxide; 2,2'-azo-bisisobutyronitrile in water; acetonitrile T=80°C; 24 h; Mechanism; Overall yield = 92 percent; Optical yield = 81.6 percent ee;