1.1: P2O5 / light petroleum / 20 °C 2.1: H2 / 5 percent Pd/C / light petroleum / 12 h / 20 °C 3.1: n-butyllithium / hexane; tetrahydrofuran / 2.5 h / -78 °C 3.2: hexane; tetrahydrofuran / -78 - 20 °C 4.1: 10 percent aq. HCl / 1 h / 20 °C View Scheme