1: 70 percent / 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide / CHCl3 / 0.25 h / Ambient temperature 2: 92 percent / 20percent H2SO4, SiO2 / CHCl3 / 6 h 3: 20 percent / hexane / 6 h / Ambient temperature; Irradiation 4: 100 percent / H2SO4 / acetic acid / 0.5 h / Heating View Scheme

1: 68 percent / 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide / CHCl3 / 0.25 h / Ambient temperature 2: 90 percent / 20percent H2SO4, SiO2 / CHCl3 / 6 h 3: 17 percent / hexane / 6 h / Ambient temperature; Irradiation View Scheme

1: 68 percent / 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide / CHCl3 / 0.25 h / Ambient temperature 2: 90 percent / 20percent H2SO4, SiO2 / CHCl3 / 6 h 3: 17 percent / hexane / 6 h / Ambient temperature; Irradiation 4: H2SO4 / acetic acid / 0.5 h / Heating View Scheme

1: 68 percent / 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide / CHCl3 / 0.25 h / Ambient temperature 2: 90 percent / 20percent H2SO4, SiO2 / CHCl3 / 6 h View Scheme