1: formic acid / tetrahydrofuran / 5 h / Heating 2: 16 percent / Na2CO3 / methanol / 4.5 h / Irradiation 3: 41 percent / pyridinium chlorochromate / CH2Cl2 View Scheme

1: 72 percent 2: 1.) 1.05 M BH3*THF; 2.) 3 M NaOH, 30percent H2O2 / 1.) THF, 90 min; 2.) 3 h 3: 41 percent / pyridinium chlorochromate / CH2Cl2 View Scheme

1: 1.) 1.05 M BH3*THF; 2.) 3 M NaOH, 30percent H2O2 / 1.) THF, 90 min; 2.) 3 h 2: 41 percent / pyridinium chlorochromate / CH2Cl2 View Scheme