1: 95 percent / iodine / CH2Cl2 / 2 h / Ambient temperature 2: 1.) potassium carbonate, 2.) Amberlite IR-120B / 1.) acetone, methanol, rt, 3 h; 2.) 20 h 3: 60 percent / borane-methyl sulfide / tetrahydrofuran / 1.) 0 deg C, 3 h; 2.) rt, 3 h View Scheme

1: 95 percent / iodine / CH2Cl2 / 2 h / Ambient temperature 2: 1.) potassium carbonate, 2.) Amberlite IR-120B / 1.) acetone, methanol, rt, 3 h; 2.) 20 h View Scheme