1.1: 65 percent / diisopropylamine; HMPA; n-butyllithium / tetrahydrofuran; hexane / 2 h / -78 °C 2.1: Pd(OH)2/C; H2 / ethyl acetate / 6 h / 20 °C 2.2: 87 percent / NaH / dimethylformamide / 2 h / 50 °C View Scheme

18-crown-6 ether in benzene T=50°C; 96 h;