1: 88 percent / NaBH4, aq. Na2CO3 / 24 h / Ambient temperature 2: 79 percent / PBr3 / diethyl ether / 3 h / Ambient temperature View Scheme

potassium hydroxide; hydrazine hydrate in diethylene glycol

1: 2,4-dibromo thiophene With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 0.5 h; Inert atmosphere; 2: N,N-dimethyl-formamide in tetrahydrofuran; hexane T=20°C; 2 h; Inert atmosphere; 3: With tert.-butyl lithium in tetrahydrofuran; hexane; pentane T=-78 - 20°C; Inert atmosphere;

(i) nBuLi, (ii) /BRN= 605365/; Multistep reaction;