dipyridinium dichromate in N,N-dimethyl-formamide 9 h;

NaH in ethyl acetate; acetone; mineral oil

1: 1.) n-BuLi, hexamethylphosphoramide (HMPA) / 1.) hexane, 5 deg C, 30 min, 2.) RT, overnight 2: p-toluenesulfonic acid / methanol / 1.5 h 3: Li, 1,3-diaminopropane, potassium tert-butoxide / 2 h 4: 86 percent / pyridinium dichromate (PDC) / dimethylformamide / 9 h View Scheme

1: 87 percent / p-toluenesulfonic acid / CH2Cl2 / 1.67 h / 0 - 20 °C 2: 1.) n-BuLi, hexamethylphosphoramide (HMPA) / 1.) hexane, 5 deg C, 30 min, 2.) RT, overnight 3: p-toluenesulfonic acid / methanol / 1.5 h 4: Li, 1,3-diaminopropane, potassium tert-butoxide / 2 h 5: 86 percent / pyridinium dichromate (PDC) / dimethylformamide / 9 h View Scheme

1: 1.) hexamethylphosphoramide (HMPA), nBuLi, 2.) HMPA / 1.) hexane, 30 min, 2.) RT, overnight 2: Li, 1,3-diaminopropane, potassium tert-butoxide / 2 h 3: 86 percent / pyridinium dichromate (PDC) / dimethylformamide / 9 h View Scheme

1: p-toluenesulfonic acid / methanol / 1.5 h 2: Li, 1,3-diaminopropane, potassium tert-butoxide / 2 h 3: 86 percent / pyridinium dichromate (PDC) / dimethylformamide / 9 h View Scheme

1: Li, 1,3-diaminopropane, potassium tert-butoxide / 2 h 2: 86 percent / pyridinium dichromate (PDC) / dimethylformamide / 9 h View Scheme

1: Li, 1,3-diaminopropane, t-BuOK / 0.75 h / Ambient temperature 2: Jones' reagent / acetone View Scheme

1: 100 percent / p-TSA / methanol / 20 °C 2: 68 percent / NaH; 1,3-diaminopropane / 70 °C 3: 69 percent / PDC / dimethylformamide View Scheme

1: Cu(OAc)2 / pyridine / 0.17 h / Heating 2: H2 / 10 percent Pd/C / CHCl3 / 20 °C 3: aq. NaOH / tetrahydrofuran / 20 °C 4: oxalyl chloride / CH2Cl2 / 12 h / 20 °C View Scheme