[Si:1]([O:8][C:9]1[CH:10]=[CH:11][C:12]([CH3:16])=[C:13](I)[CH:14]=1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].C([Li])(C)(C)C.CCCCC.[P:27](Cl)([O:32][CH2:33][CH3:34])([O:29][CH2:30][CH3:31])=[O:28]>C1COCC1.[NH4+].[Cl-].CCOC(C)=O>[Si:1]([O:8][C:9]1[CH:10]=[CH:11][C:12]([CH3:16])=[C:13]([P:27](=[O:28])([O:32][CH2:33][CH3:34])[O:29][CH2:30][CH3:31])[CH:14]=1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]To a solution of 5-tert-butyldimethylsilyloxy-2-methylphenyliodide 1-2 (250 mg, 0.72 mmol) in 5 mL of THF, chilled to −78 was added 0.85 mL of a 1.7 M solution of t-butyllithium in pentane (1.44 mmol). The resulting pale yellow solution was stirred at −78° C. for 30 min. Then diethyl chlorophosphate (0.13 mL, 0.86 mmol) in 2 mL THF was added via a cannula needle. The resulting mixture was stirred at −78° C. for 30 min, then diluted with aqueous NH4Cl and EtOAc. The organic layer was separated, washed with brine, dried (MgSO4) and evaporated. The resulting residue was subjected to MPLC on a 12 g column of SiO2 eluting with 15% EtOAc in hexanes (10 min) to provide diethyl 5-tert-butyldimethylsilyloxy-2-methylphenylphosphonate 1-3 as an oil. 1H NMR (300 MHz, DMSO-d6): δ 0.18 (s, 6H), 0.95 (s, 9H), 1.22 (t, 6H, J=6 Hz), 2.40 (d, 3H, J=1.5 Hz), 3.9-4.0 (m, 4H), 6.99 (dd, 1H, J=8, 2 Hz), 7.19 (m, 1H), 7.24 (m, 1H).
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