toluene-4-sulfonic acid in chloroform T=60°C; Cyclization; 24 h;

titanium tetrachloride in chloroform T=20°C; Cyclization; 3.5 h;

potassium hydroxide in N,N-dimethyl-formamide T=120°C; 1 h;

potassium carbonate in acetonitrile 5 h; Reflux;

1.1: n-BuLi / tetrahydrofuran; hexane / 0.83 h / -78 °C 1.2: tetrahydrofuran; hexane / -78 - 20 °C 2.1: DIBALH / diethyl ether; hexane / 20 °C 3.1: (COCl)2; DMSO; Et3N / CH2Cl2 / -78 - 20 °C 4.1: NH2OH*HCl; Na2CO3 / H2O / 20 °C 5.1: LAH / diethyl ether; diisopropyl ether / 55 °C 6.1: Et3N / CH2Cl2 7.1: 21 percent / TiCl4 / CHCl3 / 3.5 h / 20 °C View Scheme

Me6-TREN; copper(l) chloride in dichloromethane T=20°C; Rearrangement; Deacylation; Title compound not separated from byproducts.;

1: 83 percent / Et3N / CH2Cl2 / 1 h 2: 83 percent / KOH / dimethylformamide / 1 h / 120 °C View Scheme

triethylamine T=0 - 20°C; 12 h;

1: hydrazine hydrate / ethanol / 0.5 h / Heating 2: triethylamine / 12 h / 0 - 20 °C View Scheme