pyridine; sodium tetrahydroborate; chloroformic acid ethyl ester 1) tetrahydrofuran, 1 h 2) water, tetrahydrofuran, 20 deg C, 1 h; Yield given. Multistep reaction;

sodium perborate in acetic acid 1) 40 deg C, 1 h 2) 60 deg C, 1 h;

1: 1) sodium nitrite, aq. HCl 2) KI, CuI / 1) under 0 deg C 2) water, 2 h reflux 2: 100 percent / NaOH, CuI / H2O / 8 h / Heating 3: 99 percent / 1) lithium diisopropylamide / tetrahydrofuran; various solvent(s) / 1) -5 to -15 deg C, 40 min. 2) warming to 10 deg C, 3 h 4: 98 percent / polyphosphoric acid, water / 0.5 h / 140 °C 5: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

1: 96 percent / Cu2O / quinoline / 0.75 h / 185 - 190 °C 2: 99 percent / 1) lithium diisopropylamide / tetrahydrofuran; various solvent(s) / 1) -5 to -15 deg C, 40 min. 2) warming to 10 deg C, 3 h 3: 98 percent / polyphosphoric acid, water / 0.5 h / 140 °C 4: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

1: 100 percent / NaOH, CuI / H2O / 8 h / Heating 2: 99 percent / 1) lithium diisopropylamide / tetrahydrofuran; various solvent(s) / 1) -5 to -15 deg C, 40 min. 2) warming to 10 deg C, 3 h 3: 98 percent / polyphosphoric acid, water / 0.5 h / 140 °C 4: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

1: 99 percent / 1) lithium diisopropylamide / tetrahydrofuran; various solvent(s) / 1) -5 to -15 deg C, 40 min. 2) warming to 10 deg C, 3 h 2: 98 percent / polyphosphoric acid, water / 0.5 h / 140 °C 3: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

1: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

1: 98 percent / polyphosphoric acid, water / 0.5 h / 140 °C 2: 1) ethyl chloroformate, triethylamine 2) sodium borohydride / 1) tetrahydrofuran, 5 deg C, 15 min.; 15 deg C, 45 min. 2) water, 40 deg C, 4 h; 20 deg C, 18 h View Scheme

Yield given. Multistep reaction;

1: 95 percent / sodium perborate tetrahydrate / acetic acid / 1 h / 60 - 115 °C 2: 1) ethyl chloroformate, pyridine 2) sodium borohydride / 1) tetrahydrofuran, 1 h 2) water, tetrahydrofuran, 20 deg C, 1 h View Scheme