nitric acid; acetic acid in acetic anhydride T=-20 - 0°C; 2 h;

methanesulfonic acid in chloroform Cyclization; Heating;

1.1: t-BuLi / diethyl ether; pentane / 1 h / -78 °C 1.2: ZnCl2 / tetrahydrofuran / 1 h 1.3: 73 percent / Pd(dba)2; dppf / tetrahydrofuran / 18 h / 20 °C 2.1: 99 percent / LiBH4 / diethyl ether; methanol; tetrahydrofuran / 0 - 20 °C 3.1: 72 percent / PPA; MeSO3H / CHCl3 / Heating View Scheme

1: 99 percent / LiBH4 / diethyl ether; methanol; tetrahydrofuran / 0 - 20 °C 2: 72 percent / PPA; MeSO3H / CHCl3 / Heating View Scheme

1.1: 90 percent / H2SO4 / 16 h / Heating 2.1: t-BuLi / diethyl ether; pentane / 1 h / -78 °C 2.2: ZnCl2 / tetrahydrofuran / 1 h 2.3: 73 percent / Pd(dba)2; dppf / tetrahydrofuran / 18 h / 20 °C 3.1: 99 percent / LiBH4 / diethyl ether; methanol; tetrahydrofuran / 0 - 20 °C 4.1: 72 percent / PPA; MeSO3H / CHCl3 / Heating View Scheme

1: 83 percent / aluminum chloride / nitromethane / 0.25 h 2: nitric acid, acetic acid / acetic anhydride / 2 h / -20 - 0 °C View Scheme