1: 83 percent / 1.8M EtAlCl2 / toluene; diethyl ether / -40 - 0 °C 2: H2 / 10percent Pd-C / tetrahydrofuran / 8 h / Ambient temperature 3: 71 percent / TBAF*3H2O / tetrahydrofuran / 0.17 h / -90 °C View Scheme

1: 83 percent / 1.8M EtAlCl2 / toluene; diethyl ether / -40 - 0 °C 2: H2 / 10percent Pd-C / tetrahydrofuran / 8 h / Ambient temperature 3: 71 percent / TBAF*3H2O / tetrahydrofuran / 0.17 h / -90 °C 4: 89 percent / Ph3P, diethyl azodicarboxylate / tetrahydrofuran / 18 h / Ambient temperature View Scheme

1: 83 percent / 1.8M EtAlCl2 / toluene; diethyl ether / -40 - 0 °C 2: H2 / 10percent Pd-C / tetrahydrofuran / 8 h / Ambient temperature 3: 71 percent / TBAF*3H2O / tetrahydrofuran / 0.17 h / -90 °C View Scheme