1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Inert atmosphere; 2: hexanoic acid methyl ester in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere;

1.1: thionyl chloride; N,N-dimethyl-formamide / dichloromethane / 2 h / 10 - 20 °C / |Inert atmosphere 2.1: dichloromethane / 1 h / 5 - 20 °C / |Inert atmosphere 3.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / -78 - -75 °C / |Inert atmosphere 3.2: 1 h / -78 - 20 °C / |Inert atmosphere View Scheme

1.1: dichloromethane / 1 h / 5 - 20 °C / |Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / -78 - -75 °C / |Inert atmosphere 2.2: 1 h / -78 - 20 °C / |Inert atmosphere View Scheme

(i) NaH, THF, (ii) nBuLi, hexane, (iii) /BRN= 1098260/; Multistep reaction;

1: SOCl2 View Scheme

(i) nBuLi, hexane, THF, (ii) Cu2I2, (iii) /BRN= 506332/, Et2O; Multistep reaction;

1: (2-oxoheptyl)phosphonic acid dimethyl ester With lithium hydroxide in tert-butyl methyl ether T=20°C; 1 h; 2: (3aR,4R,5R,6aS)-5-(benzoyloxy)hexahydro-2H-cyclopenta[b]furan-2-one-4-carboxaldehyde in tert-butyl methyl ether; water T=20°C; 1 h;

sodium hexamethyldisilazane in tetrahydrofuran T=-78 - 20°C; Horner-Emmons reaction;

lithium hexamethyldisilazane in tetrahydrofuran T=-78 - 20°C; Horner-Emmons reaction;

1: 1) NaH / 1) THF, 23 deg C, 30 min, 2) THF, 23 deg C, 40 min 2: 81 mg / NaBH4 / methanol / 0.67 h / -25 °C 3: 65percent aq. acetic acid / tetrahydrofuran / 2 h / 50 °C 4: 90 percent / imidazole / dimethylformamide / 1 h / 23 °C 5: 95 percent / H2 / napthalene*Cr(CO)3 / tetrahydrofuran / 23 h / 45 °C / 55163.1 Torr 6: 100 percent / tetrabutylammonium fluoride (TBAF) / tetrahydrofuran / 13 h / 23 °C 7: 100 percent / 10percent aq. NaOH / methanol / 13 h / 0 °C View Scheme