1: 0.41 g / 15percent HClO4 / 8 h / Heating 2: 79 percent / trifluoroacetic anhydride / tetrahydrofuran / 12 h / Ambient temperature 3: 59 percent / LiI / dimethylformamide / 5 h / Heating View Scheme

With  air in  sodium hydroxide; ethanol 24 h;  Ambient temperature;   

Multi-step reaction with 4 steps 1: LDA / tetrahydrofuran; hexane / Ambient temperature2: diethyl ether3: 75 percent / NaOMe / methanol / 18 h / Heating4: 82 percent / air / ethanol; aq. NaOH / 24 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 75 percent / NaOMe / methanol / 18 h / Heating2: 82 percent / air / ethanol; aq. NaOH / 24 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 0.41 g / 15percent HClO4 / 8 h / Heating2: 79 percent / trifluoroacetic anhydride / tetrahydrofuran / 12 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 0.41 g / 15percent HClO4 / 8 h / Heating2: 33 percent / BBr3 / CH2Cl2 / -78 deg C then r.t., 1 h