1: 81 percent / H2SO4 / CHCl3 / 16 h / Heating 2: 85 percent / H2 / PtO2 / methanol / 7 h 3: 88 percent / pyridine / 336 h 4: 80 percent / NH4Br, NH3 / 144 h / Ambient temperature 5: 59 percent / NaN3 / methanol; H2O / 20 h / Heating 6: 81 percent / H2 / PtO2 / methanol / 6 h / Ambient temperature 7: 79 percent / HCl / H2O / 20 h / Heating View Scheme

1: 81 percent / H2SO4 / CHCl3 / 16 h / Heating 2: 85 percent / H2 / PtO2 / methanol / 7 h 3: 88 percent / pyridine / 336 h 4: 1. NH4Br, NH3; 2. HCl / 1. 88 deg C, 16 h; 2. H2O, 88 deg C, 20 h, heating View Scheme

1: 81 percent / H2SO4 / CHCl3 / 16 h / Heating 2: 85 percent / H2 / PtO2 / methanol / 7 h 3: 88 percent / pyridine / 336 h 4: 1. NH4Br, NH3; 2. HCl / 1. 88 deg C, 16 h; 2. H2O, 88 deg C, 20 h, heating View Scheme

1: 3-(benzyloxy)cyclobutane-1-carboxylic acid With diphenyl phosphoryl azide; N-ethyl-N,N-diisopropylamine in toluene T=80°C; 7 h; Inert atmosphere; 2: potassium tert-butylate in tetrahydrofuran; toluene T=0 - 20°C; 1 h; Inert atmosphere;

diphenyl phosphoryl azide; triethylamine 20 h; Heating / reflux;

1: 99.5 percent / oxalyl chloride / CCl4 / 1) 0 deg C, 1 h, 2) r.t., 12 h 2: CCl4 / 5 h / Ambient temperature 3: 91.9 percent / LiAlH4 / 1,2-dimethoxy-ethane / 60 h / 85 °C 4: 81.2 percent / imidazole / dimethylformamide / 20 h / Ambient temperature 5: 99.2 percent / H2 / Pd/C / 1,2-dimethoxy-ethane / 8 h / 760 Torr / Ambient temperature 6: 76.2 percent / Et3N / CH2Cl2 / 15 h / Ambient temperature 7: 46.9 percent / DBU / dimethylsulfoxide / 35 h / 80 °C 8: 60 mg / aq. HF-urea / tetrahydrofuran / 15 h / Ambient temperature View Scheme

2: H2 / Pd-C View Scheme

sulfuric acid in chloroform 16 h; Heating;

1: H2SO4 / 1,2-dichloro-ethane 2: H2 / Pd / methanol 3: (i) PhSO2Cl, Py, (ii) LiBr, acetone View Scheme

1: H2SO4 / 1,2-dichloro-ethane 2: H2 / Pd / methanol 3: (i) PhSO2Cl, Py, (ii) LiBr, acetone 4: NaH, 4-tert-butyl-benzene-1,2-diol / diethyl ether View Scheme