1: With n-butyllithium in tetrahydrofuran; hexane 1.5 h; Cooling with acetone-dry iceInert atmosphere; 2: With tri-isopropoxy-borane in tetrahydrofuran; hexane 3.83333 h; 3: With water; ammonium chloride in tetrahydrofuran; hexane pH=8; Cooling;

hydrogenchloride in tetrahydrofuran; hexane; water

1.1: trifluoroacetic acid; triethylsilane / 4 h / 20 - 50 °C 2.1: n-butyllithium / hexane; tetrahydrofuran / 1.5 h / Cooling with acetone-dry ice; Inert atmosphere 2.2: 3.83 h 2.3: pH 8 / Cooling View Scheme

1.1: polyphosphoric acid / 1 h / 90 °C 2.1: trifluoroacetic acid; triethylsilane / 4 h / 20 - 50 °C 3.1: n-butyllithium / hexane; tetrahydrofuran / 1.5 h / Cooling with acetone-dry ice; Inert atmosphere 3.2: 3.83 h 3.3: pH 8 / Cooling View Scheme