1: 1-amino-1-cyclo-hexanecarboxylic acid With sodium hydroxide in water T=80°C; 2 h; 2: furan-2-carbonyl chloride With sodium hydroxide in water T=0 - 20°C; 3: With hydrogenchloride in water T=0°C;

1: furan With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 1 h; Inert atmosphere; 2: Spirolt;4.5gt;decan-2,4'-oxazolidine-2,5'-dione in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere;

sodium hydroxide in methanol; water 3 h; Heating / reflux;

1.1: tetrahydrofuran / 3 h / 50 °C / |Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 - 0 °C / |Inert atmosphere 2.2: -78 - 20 °C / |Inert atmosphere View Scheme

1.1: phosphorus trichoride / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 - 0 °C / |Inert atmosphere 2.2: -78 - 20 °C / |Inert atmosphere View Scheme

1.1: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 2 h / 20 °C / |Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 - 0 °C / |Inert atmosphere 2.2: -78 - 20 °C / |Inert atmosphere View Scheme