1.1: 92 percent / LHMDS / tetrahydrofuran / -78 - 20 °C 2.1: trifluoroacetic acis / CH2Cl2 / 20 °C 2.2: 90 percent / Et3SiH / CH2Cl2 / 1 h 3.1: 78 percent / Zn / acetic acid / Heating View Scheme

1.1: 93 percent / LHMDS / tetrahydrofuran / -78 - 20 °C 2.1: trifluoroacetic acis / CH2Cl2 / 20 °C 2.2: 91 percent / Et3SiH / CH2Cl2 / 1 h 3.1: 69 percent / Zn / acetic acid / Heating View Scheme