1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran T=-78°C; 0.5 h; Inert atmosphere; 2: methyl 2-[3-(trifluoromethyl)phenoxy]acetate in tetrahydrofuran T=-78 - 20°C; 2.5 h; Inert atmosphere;

n-butyllithium in tetrahydrofuran; hexane

1.1: potassium carbonate / acetone / 15 h / Reflux 2.1: n-butyllithium / tert-butyl methyl ether; hexanes / 4 h / -75 - -65 °C / Inert atmosphere 2.2: 21 h / -70 - 20 °C / Inert atmosphere 2.3: 0 - 25 °C View Scheme

1: 1.) NaH / 1.) THF, 90 min, 2.) THF, 30 min 2: lithium triethylborohydride / tetrahydrofuran / 0.5 h 3: potassium carbonate / methanol; tetrahydrofuran / 2.5 h View Scheme

1: 1.) NaH / 1.) THF, 25 deg C, 20 min, 2.) THF, from 25 deg C to 60 deg C, 4.5 h 2: NaBH4 / methanol; tetrahydrofuran / -45 °C 3: K2CO3 / methanol / 1 h / 50 °C 4: p-toluenesulfonic acid / CH2Cl2 / 0.33 h / 25 °C 5: 1.) LDA / 1.) THF, hexane, -78 deg C, 20 min, 2.) THF, hexane, a) -78 deg C, 30 min, b) 20 deg C, 30 min 6: 85 percent / 30percent H2O2 / ethyl acetate; methanol / 0.33 h / 40 °C 7: 71 percent / 65percent aq. acetic acid / tetrahydrofuran / 0.33 h / 70 °C View Scheme

1: dimethyl [3-(3-(trifluoromethyl)phenoxy)-2-oxopropyl]phosphonate With potassium tert-butylate in tetrahydrofuran T=0 - 5°C; 2: With zinc(II) chloride in tetrahydrofuran T=15 - 20°C; 1 h; 3: (1S,5R,6R,7R)-6-formyl-7-lt;(4-phenylbenzoyl)oxygt;-2-oxabicyclolt;3.3.0gt;octan-3-one in tetrahydrofuran; dichloromethane T=5 - 10°C;

1: dimethyl [3-(3-(trifluoromethyl)phenoxy)-2-oxopropyl]phosphonate With sodium hydride in dichloromethane T=0°C; 1 h; 2: (3aR,4R,6aS)-4-formyl-2-oxohexahydro-2H-cyclopenta[b]furan-5-yl biphenyl-4-carboxylate in dichloromethane T=0 - 5°C;