pyridine in dichloromethane T=20°C; 1 h;

n-butyllithium in tetrahydrofuran; diethyl ether T=-78°C;

1: 100 percent / 70 °C 2: 57 percent / n-BuLi / tetrahydrofuran; diethyl ether / -78 °C View Scheme

1: N-bromosuccinmide; dibenzoyl peroxide / benzene / 4 h / Reflux; Inert atmosphere 2: pyridine / dichloromethane / 0 - 20 °C / Inert atmosphere View Scheme

1: With n-butyllithium in tetrahydrofuran T=-78 - 20°C; Cycloaddition; Diels-Alder reaction; 2: With hydrogenchloride Ring cleavage; 5 h; Further stages.;

1: With n-butyllithium in tetrahydrofuran T=-78 - 20°C; Cycloaddition; Diels-Alder reaction; 2: With hydrogenchloride Ring cleavage; 5 h; Further stages.;

cesium fluoride; tris(dibenzylideneacetone)dipalladium (0) in acetonitrile T=20°C;

1.1: Pd2(dba)3; 1,3-bis(diphenylphosphino)propane; LiBr / diethyl ether / 7 h / 20 °C 2.1: n-BuLi / diethyl ether; hexane / 0.25 h / -78 °C 2.2: 4.04 g / diethyl ether; hexane / 3 h / -78 - 20 °C View Scheme

1.1: Pd2(dba)3; 1,3-bis(diphenylphosphino)propane; LiBr / diethyl ether / 7 h / 20 °C 2.1: n-BuLi / diethyl ether; hexane / 0.25 h / -78 °C 2.2: 4.04 g / diethyl ether; hexane / 3 h / -78 - 20 °C 3.1: 80 percent / silver(I) carbonate; Pd(PPh3)4 / benzene / 96 h / Heating View Scheme

1.1: Pd2(dba)3; 1,3-bis(diphenylphosphino)propane; LiBr / diethyl ether / 7 h / 20 °C 2.1: n-BuLi / diethyl ether; hexane / 0.25 h / -78 °C 2.2: 4.04 g / diethyl ether; hexane / 3 h / -78 - 20 °C 3.1: 80 percent / silver(I) carbonate; Pd(PPh3)4 / benzene / 96 h / Heating 4.1: 99 percent / i-PrMgCl / tetrahydrofuran / 2 h / 20 °C View Scheme