1: 77 percent / n-BuLi / tetrahydrofuran / 1) ice bath, 2) r.t, overnight 2: 72 percent / 1.) KHSO4, 2.) H2O / acetone / 4.5 h / 60 °C 3: 65 percent / NH2OH*HCl, NaOAc / ethanol / 2 h / Heating 4: 70 percent / decahydronaphthalene / 200 °C View Scheme

1: 3-(1,3-dioxolane-2-yl)-thiophene With n-butyllithium in tetrahydrofuran 2: N,N-dimethyl-formamide in tetrahydrofuran T=-5°C;

n-butyllithium; ammonium chloride in tetrahydrofuran; N,N-dimethyl-formamide