1: formaldehyd; cyclopenta-1,3-diene With ammonium chloride in water T=20°C; 36 h; 2: benzyl chloroformate With sodium carbonate in water T=0°C; 2 h;

1: (-)-2-azabicyclo[2.2.1]hept-5-en-3-one With lithium aluminium tetrahydride in tetrahydrofuran; diethyl ether T=0°C; 5.5 h; Heating / reflux; 2: With sodium hydroxide; water in tetrahydrofuran; diethyl ether T=20°C; 3: benzyl chloroformate in tetrahydrofuran; diethyl ether; water T=20°C; 1 h;

sodium carbonate in water T=0°C; 2 h; Yield given;

1: NH4Cl / H2O / 36 h / Ambient temperature 2: Na2CO3 / H2O / 2 h / 0 °C View Scheme

1.1: borane-THF / tetrahydrofuran / 2.67 h / -78 - 20 °C 1.2: 0.5 h 2.1: Jone's reagent / acetone / 3 h / 0 °C 3.1: hydroxylamine hydrochloride; sodium acetate / ethanol; water / 2 h / 20 °C 4.1: sodium carbonate / water; acetone / 0.17 h 4.2: 16 h 5.1: hydrogenchloride / water; acetone / 16 h / 20 °C View Scheme

1: 1.) Hg(OAc)2, 2.) 0.5 M NaBH4 in 3 N NaOH / 1.) H2O, THF, RT, 12 h, 2.) H2O, THF, 0 deg C 2: 62 percent / Jones reagent / acetone / 3 h / Ambient temperature View Scheme

1: With borane-THF in tetrahydrofuran T=-78 - 20°C; 2.66667 h; 2: With water; dihydrogen peroxide; sodium hydroxide in tetrahydrofuran 0.5 h;