1: With sodium hydroxide; water in tetrahydrofuran 72 h; Heating / reflux; 2: With hydrogenchloride; water

1: benzo[b]thiophene With n-butyllithium in tetrahydrofuran; cyclohexane T=-78°C; 1 h; Inert atmosphere; 2: Spirolt;4.5gt;decan-2,4'-oxazolidine-2,5'-dione in tetrahydrofuran; cyclohexane T=-78 - 20°C; Inert atmosphere;

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