1: With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran T=-80°C; 0.75 h; 2: With iodine in tetrahydrofuran T=-80°C; 0.75 h;

1: With 2,2,6,6-tetramethylpiperidinyl-lithium in tetrahydrofuran; hexane T=-78°C; 2: With iodine in tetrahydrofuran; hexane T=-78 - 20°C; Further stages.;