1.1: n-butyllithium; diisopropylamine / tetrahydrofuran; hexane / -10 - 20 °C 1.2: 55 percent / p-toluenesulfonyl chloride / tetrahydrofuran; hexane / -78 °C 2.1: 80 percent / 210 °C View Scheme

1: 62 percent / 10 percent HCl / ethanol / 24 h / 40 °C 2: 76 percent / 210 - 230 °C View Scheme