C([Li])CCC.[CH3:6][P:7](=[O:12])([O:10][CH3:11])[O:8][CH3:9].[Si:13]([O:20][CH:21]([CH2:28][CH2:29][CH3:30])[CH2:22][C:23](OCC)=[O:24])([C:16]([CH3:19])([CH3:18])[CH3:17])([CH3:15])[CH3:14]>C1COCC1>[CH3:9][O:8][P:7]([CH2:6][C:23](=[O:24])[CH2:22][CH:21]([O:20][Si:13]([C:16]([CH3:19])([CH3:18])[CH3:17])([CH3:14])[CH3:15])[CH2:28][CH2:29][CH3:30])(=[O:12])[O:10][CH3:11]n-Butyllithium (6.8 mL of a 1.6M solution in THF, 10.94 mmol) was added to a solution of dimethyl methylphosphonate (1.2 mL, 10.94 mmol) in THF (22 mL) at −78° C. After 0.5 h a solution of the ester 2 (2.0 g, 7.29 mmol) in THF (4 mL) was added. The reaction solution was allowed to warm to room temperature overnight on its own accord. After 16 h the reaction was quenched with saturated aqueous ammonium chloride and extracted with EtOAc. The organic portion was washed with brine, dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (silica gel, 2:1 hex/EtOAc followed by 1:1 hex/EtOAc) afforded 0.93 g (36%) of phosphonate 3 (see Scheme 1).
Wird geladen…
