in toluene

1: 77 percent / butyl-lithium / tetrahydrofuran 2: 75 percent 3: 92 percent / 1.) ozone, 2.) hydrogen peroxide, formic acid 4: 8 percent / 1.) NaBH4, 2.) trifluoroacetic anhydride / 1.) NaBH4, ethanol, 2.) trifluoroacetic anhydride, benzene 5: 55 percent / KOH / tetrahydrofuran; H2O; dimethylsulfoxide / 1.) aq. KOH, THF, room temperatures, 20h, 2.) DMSO, 50 deg. C, 1h View Scheme