1: 2,2,6,6-tetramethyl-piperidine With n-butyllithium in tetrahydrofuran; hexane T=-10°C; 0.166667 h; 2: tri-isopropoxy-borane; alpha-chloronaphthalene in tetrahydrofuran; hexane T=-78 - 20°C; 3: 3-hydroxy-2,2-dimethylpropanol With acetic acid in tetrahydrofuran; hexane T=20°C; 1 h; Further stages.;