1: 90.8 percent / conc.H2SO4 / 4 h / Heating 2: 80.7 percent Turnov. / Ba(OH)2*8H2O / methanol; benzene / 20 h / Ambient temperature 3: 45 percent / lead tetraacetate, pyridine, Cu(OAc)2 / benzene / 3 h / Heating 4: 1) Br2, 2) aq.KOH / 1) CCl4, r.t., 2) 135-145 deg C, 4 h 5: 86.2 percent / conc.H2SO4 / 4 h / Heating 6: 96 percent / LAH / diethyl ether / 2 h / Ambient temperature 7: 90.6 percent / PPTS / CH2Cl2 / 4 h / Ambient temperature View Scheme

1: 45 percent / lead tetraacetate, pyridine, Cu(OAc)2 / benzene / 3 h / Heating 2: 1) Br2, 2) aq.KOH / 1) CCl4, r.t., 2) 135-145 deg C, 4 h 3: 86.2 percent / conc.H2SO4 / 4 h / Heating 4: 96 percent / LAH / diethyl ether / 2 h / Ambient temperature 5: 90.6 percent / PPTS / CH2Cl2 / 4 h / Ambient temperature View Scheme

1: 80.7 percent Turnov. / Ba(OH)2*8H2O / methanol; benzene / 20 h / Ambient temperature 2: 45 percent / lead tetraacetate, pyridine, Cu(OAc)2 / benzene / 3 h / Heating 3: 1) Br2, 2) aq.KOH / 1) CCl4, r.t., 2) 135-145 deg C, 4 h 4: 86.2 percent / conc.H2SO4 / 4 h / Heating 5: 96 percent / LAH / diethyl ether / 2 h / Ambient temperature 6: 90.6 percent / PPTS / CH2Cl2 / 4 h / Ambient temperature View Scheme

1: 1) Br2, 2) aq.KOH / 1) CCl4, r.t., 2) 135-145 deg C, 4 h 2: 86.2 percent / conc.H2SO4 / 4 h / Heating 3: 96 percent / LAH / diethyl ether / 2 h / Ambient temperature 4: 90.6 percent / PPTS / CH2Cl2 / 4 h / Ambient temperature View Scheme

1: n-butyllithium / tetrahydrofuran / 15 h / |Inert atmosphere; |Reflux 2: toluene-4-sulfonic acid / 16 h / 20 °C / |Inert atmosphere 3: lithium; 1,3-diamino-propane; potassium tert-butylate / |Inert atmosphere 4: toluene-4-sulfonic acid View Scheme

toluene-4-sulfonic acid

1: n-BuLi / tetrahydrofuran; hexane / 1.) 0 deg C, 30 min, 2.) r.t., 70 min 2: p-TsOH*H2O / methanol / 1 h / Ambient temperature 3: 99 percent / pyridine / 3.5 h / Ambient temperature 4: 73 percent / dichloromaleic anhydride / 200 °C 5: 99 percent / 2 M KOH / ethanol / 19 h / Heating 6: 72 percent / CBr4, PPh3 / CH2Cl2 / 6 h / Ambient temperature 7: n-BuLi / hexane; tetrahydrofuran; hexamethylphosphoric acid triamide / 1.) -78 deg C, 3.5 h, 2.) -78 deg C to r.t., 17 h 8: p-TsOH*H2O / methanol / 1 h / Heating 9: 68 percent / CBr4, PPh3 / diethyl ether; CH2Cl2 / 1.) 0 deg C, 1 h, 2.) r.t., 17 h 10: 1.) EtMgBr, 2.) CuCN / 1.) THF, reflux, 1 h; r.t., 15 min, 2.) 0 deg C, 1 h; r.t., 2.75 h 11: H2, quinoline / 5percent Pd/BaSO4 / pyridine / Ambient temperature 12: 69 percent / AlI3, (+)-limonene / CS2 / 1.) r.t., 10 min, 2.) reflux, 30 min View Scheme

1: 1.) EtMgBr, 2.) CuI 2: 89 percent / pyridinium chlorochromate / CH2Cl2 / 2 h 3: diethyl ether; tetrahydrofuran / 1 h / 1.) 0 deg C, 0.5 h, 2.) 25 deg C, 0.5 h 4: tetrahydrofuran / 1 h / Ambient temperature 5: O3 / cyclohexane; acetic acid / 5 °C 6: aq. H2CrO4 / cyclohexane; acetic acid / 4 h / 20 °C 7: 94 percent / K2CO3 / methanol / 2 h / 50 °C View Scheme

1: 1.) EtMgBr, 2.) CuI 2: 89 percent / pyridinium chlorochromate / CH2Cl2 / 2 h 3: diethyl ether; tetrahydrofuran / 1 h / 1.) 0 deg C, 0.5 h, 2.) 25 deg C, 0.5 h 4: tetrahydrofuran / 1 h / Ambient temperature 5: O3 / cyclohexane; acetic acid / 5 °C 6: aq. H2CrO4 / cyclohexane; acetic acid / 4 h / 20 °C 7: 94 percent / K2CO3 / methanol / 2 h / 50 °C 8: 93 percent / NaBH4, NaOH, Ni(OAc)2*4H2O, ethylene diamine, H2 / ethanol / 2 h / 20 °C View Scheme

1: 65 percent / n-BuLi, BF3*Et2O / tetrahydrofuran; hexane / -78 °C 2: 90 percent / Na/liq. NH3 / tetrahydrofuran / 4 h / -33 °C 3: 87 percent / pyridine View Scheme