in N,N-dimethyl-formamide T=60°C; 5 h;

1: 62 percent / tetrahydrofuran 2: 85 percent / pyridine / CHCl3 / 8 h / 60 °C 3: 1) dimethyldioxirane / 1) acetone, 15 min, RT, 2) toluene, reflux, 2 h View Scheme

1: 62 percent / tetrahydrofuran 2: 58 percent / pyridine / CHCl3 / 8 h / 60 °C 3: 1) dimethyldioxirane / 1) acetone, 15 min, RT, 2) toluene, reflux, 2 h View Scheme

2: 58.7 percent 3: 72.9 percent 4: 78.8 percent 5: 78.5 percent / MCPBA (70percent) / CH2Cl2 / 2 h / 0 °C 6: 1.) magnesium methoxide / 1.) methanol, rt., 16 h; 2.) benzene, reflux, 3 h 7: 61.3 percent / acetic acid / 1 h / Heating View Scheme

1: 62 percent / tetrahydrofuran 2: 63 percent / pyridine / CHCl3 / 8 h / 60 °C 3: 1) dimethyldioxirane / 1) acetone, 15 min, RT, 2) toluene, reflux, 2 h View Scheme