1: With triethylamine; isobutyl chloroformate in tetrahydrofuran T=-40 - -20°C; 0.75 h; Cooling with isopropanol-dryice; 2: With sodium tetrahydroborate in tetrahydrofuran; water T=0 - 20°C; 3 h;

1: DCC / tetrahydrofuran / 0 °C 2: dicyclohexylamine (DCHA) / tetrahydrofuran / 0 °C 3: 70percent perchloric acid / Ambient temperature 4: 100 percent / 1 M KOH / methanol 5: triethylamine / tetrahydrofuran / 1 h / 0 °C 6: sodium borohydride / tetrahydrofuran; H2O / 4 h / Ambient temperature View Scheme

1: 70percent perchloric acid / Ambient temperature 2: 100 percent / 1 M KOH / methanol 3: triethylamine / tetrahydrofuran / 1 h / 0 °C 4: sodium borohydride / tetrahydrofuran; H2O / 4 h / Ambient temperature View Scheme

1: 100 percent / 1 M KOH / methanol 2: triethylamine / tetrahydrofuran / 1 h / 0 °C 3: sodium borohydride / tetrahydrofuran; H2O / 4 h / Ambient temperature View Scheme

1: dicyclohexylamine (DCHA) / tetrahydrofuran / 0 °C 2: 70percent perchloric acid / Ambient temperature 3: 100 percent / 1 M KOH / methanol 4: triethylamine / tetrahydrofuran / 1 h / 0 °C 5: sodium borohydride / tetrahydrofuran; H2O / 4 h / Ambient temperature View Scheme

triethylamine in tetrahydrofuran T=-10 - 0°C; Esterification; 0.5 h;

1: CBr4, PPh3 / CH2Cl2 / 0.05 h / Ambient temperature 2: 80 percent / NaH / tetrahydrofuran / Ambient temperature View Scheme