1: With trimethyl-oxonium tetrafluoroborate in acetonitrile T=20°C; 0.0833333 h; 2: With sodium tetrahydroborate in acetonitrile T=-20 - 20°C; 1 h;

1.1: EtMgBr / toluene; tetrahydrofuran; diethyl ether / 0.33 h / 45 °C 1.2: 59 percent / toluene; tetrahydrofuran; diethyl ether / 0.33 h / 45 °C 2.1: Me3OBF4 / acetonitrile / 0.08 h / 20 °C 2.2: 61 percent / NaBH4 / acetonitrile / 1 h / -20 - 20 °C View Scheme

(i) AgClO4, THF, (ii) H2S, MeOH, (iii) Raney-Ni, aq. NH3; Multistep reaction;