1: With tri-isopropoxy-borane; sec.-butyllithium in tetrahydrofuran; hexane; cyclohexane T=-78°C; 1 h; 2: With tri-isopropoxy-borane in tetrahydrofuran; hexane; cyclohexane T=-78 - 20°C; 3: With hydrogenchloride in tetrahydrofuran; hexane; cyclohexane; water pH=1;