1: With trifluoroacetic acid in toluene T=140°C; Pictet-Spengler cyclisation; 0.5 h; Microwave irradiation; 2: With sodium hydroxide in water pH=8;

triethylsilane; boron trifluoride diethyl etherate in dichloromethane T=-78 - 20°C; 19 h;

1.1: s-BuLi; TMEDA / diethyl ether; tetrahydrofuran; hexane / -78 - -40 °C 1.2: 54 percent / trimethylaluminum / various solvents / 17 h / -40 °C 2.1: BH3*THF / tetrahydrofuran / 4 h / Heating 2.2: 83 percent / aqueous HCl / tetrahydrofuran / 0.02 h / Heating 3.1: 94 percent / methanol / 22 h / Heating 4.1: TFAA; TFA / toluene / 15 h / Heating 5.1: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

1: 94 percent / methanol / 22 h / Heating 2: TFAA; TFA / toluene / 15 h / Heating 3: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

1.1: BH3*THF / tetrahydrofuran / 4 h / Heating 1.2: 83 percent / aqueous HCl / tetrahydrofuran / 0.02 h / Heating 2.1: 94 percent / methanol / 22 h / Heating 3.1: TFAA; TFA / toluene / 15 h / Heating 4.1: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

1.1: s-BuLi; TMEDA / diethyl ether; tetrahydrofuran; hexane / -78 - -40 °C 1.2: 54 percent / trimethylaluminum / various solvents / 17 h / -40 °C 2.1: BH3*THF / tetrahydrofuran / 4 h / Heating 2.2: 83 percent / aqueous HCl / tetrahydrofuran / 0.02 h / Heating 3.1: 94 percent / methanol / 22 h / Heating 4.1: TFAA; TFA / toluene / 15 h / Heating 5.1: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

1.1: 100 percent / diethyl ether / 0 - 20 °C 2.1: s-BuLi; TMEDA / diethyl ether; tetrahydrofuran; hexane / -78 - -40 °C 2.2: 54 percent / trimethylaluminum / various solvents / 17 h / -40 °C 3.1: BH3*THF / tetrahydrofuran / 4 h / Heating 3.2: 83 percent / aqueous HCl / tetrahydrofuran / 0.02 h / Heating 4.1: 94 percent / methanol / 22 h / Heating 5.1: TFAA; TFA / toluene / 15 h / Heating 6.1: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

1: 83 percent / aqueous HCl / acetone / 0 - 20 °C 2: 92 percent / BF3*OEt2; Et3SiH / CH2Cl2 / 19 h / -78 - 20 °C View Scheme

1: TFAA; TFA / toluene / 15 h / Heating 2: Raney nickel W2; hydrogen / ethanol / 22 h / Heating View Scheme

Raney nickel W2; hydrogen in ethanol 22 h; Heating; Title compound not separated from byproducts;