1: 3,4-dihydro-2H-1-benzopyran With n-butyllithium in diethyl ether; hexane T=20°C; 2.66667 h; Heating / reflux; 2: carbon dioxide in diethyl ether; hexane T=20°C;

hydrogenchloride 18 h; Heating;

1: 70 percent / K2CO3 / acetone / 60 h 2: 99.8 percent / 15 h / Heating 3: NaH / 1) 20 min at 0 deg C 2) reflux for 12 h 4: NaOH / 1) 1h reflux with NaOH 2) concentrated HCl 5: SOCl2 6: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 7: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 8: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: 99.8 percent / 15 h / Heating 2: NaH / 1) 20 min at 0 deg C 2) reflux for 12 h 3: NaOH / 1) 1h reflux with NaOH 2) concentrated HCl 4: SOCl2 5: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 6: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 7: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: SOCl2 2: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 3: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 4: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: NaOH / 1) 1h reflux with NaOH 2) concentrated HCl 2: SOCl2 3: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 4: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 5: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 2: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 3: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 2: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

1: NaH / 1) 20 min at 0 deg C 2) reflux for 12 h 2: NaOH / 1) 1h reflux with NaOH 2) concentrated HCl 3: SOCl2 4: 1) BF3*THF 2) NaOH, 30percent H2O2 / 2) at 55-60 deg C for 90 min 5: 72 percent / NaH / tetrahydrofuran / 20 h / Heating 6: 65 percent / 4.5M HCl / 18 h / Heating View Scheme

thionyl chloride T=90°C; 3 h;