1: in tetrahydrofuran T=-78°C; 1 h; 2: With triethylsilane; trimethylsilyl trifluoromethanesulfonate in tetrahydrofuran T=-78 - 20°C; Further stages.;

1.1: imidazole / dimethylformamide / 20 °C 2.1: tetrahydrofuran / 2.5 h / -78 °C 2.2: Et3SiH / acetonitrile / -40 °C View Scheme