hydrogenchloride; oxygen; copper dichloride; palladium dichloride P=1 Torr; 2 h;

in tetrahydrofuran T=0°C; 4 h;

sodium methylate

2: 73 percent / HMPT / tetrahydrofuran 3: TBAF / tetrahydrofuran 4: Et3N / CH2Cl2 5: 91 percent / MeONa View Scheme

1: 73 percent / HMPT / tetrahydrofuran 2: TBAF / tetrahydrofuran 3: Et3N / CH2Cl2 4: 91 percent / MeONa View Scheme

1: TBAF / tetrahydrofuran 2: Et3N / CH2Cl2 3: 91 percent / MeONa View Scheme

1: dimethyl lt;1-(methoxycarbonyl)ethylgt;phosphonate With sodium hydride in tetrahydrofuran; mineral oil T=0 - 40°C; Horner-Wadsworth-Emmons olefination; 2: pentanal in tetrahydrofuran; mineral oil Horner-Wadsworth-Emmons olefination; 24 h; Reflux; optical yield given as percent de;

1: 1.) dibal-H / 1.) ether, 40 deg C, 2 h, 2.) n-heptane, a) 0 deg C, 30 min, b) 60 deg C, 3 h 2: BF3*OEt2 / 16 h / 60 - 70 °C 3: 1.) lithium diisopropylamide, HMPA, 2.) methanol / 1.) THF, n-hexane, -78 deg C, 2 h, 2.) -78 deg C, 15 min 4: 1.) lithium diisopropylamide / 1.) THF, -78 deg C, 2 h, 2.) a) -78 deg C, 30 min, b) 0 deg C, 1 h 5: 1.) 1 M n-Bu4NF, 2.) H2O / 1.) THF, 0 deg C, 1 h, 2.) 15 min View Scheme

1: BF3*OEt2 / 16 h / 60 - 70 °C 2: 1.) lithium diisopropylamide, HMPA, 2.) methanol / 1.) THF, n-hexane, -78 deg C, 2 h, 2.) -78 deg C, 15 min 3: 1.) lithium diisopropylamide / 1.) THF, -78 deg C, 2 h, 2.) a) -78 deg C, 30 min, b) 0 deg C, 1 h 4: 1.) 1 M n-Bu4NF, 2.) H2O / 1.) THF, 0 deg C, 1 h, 2.) 15 min View Scheme

1: 1.) lithium diisopropylamide, HMPA, 2.) methanol / 1.) THF, n-hexane, -78 deg C, 2 h, 2.) -78 deg C, 15 min 2: 1.) lithium diisopropylamide / 1.) THF, -78 deg C, 2 h, 2.) a) -78 deg C, 30 min, b) 0 deg C, 1 h 3: 1.) 1 M n-Bu4NF, 2.) H2O / 1.) THF, 0 deg C, 1 h, 2.) 15 min View Scheme