[F:1][CH:2]([P:4](=[O:11])([O:8][CH2:9][CH3:10])[O:5][CH2:6][CH3:7])[F:3].[Li+].CC([N-]C(C)C)C.[I:20][CH2:21][CH2:22][O:23][CH2:24][CH2:25][O:26][CH2:27][CH2:28]I>C1COCC1.CCCCCCC.C1COCC1.C(C1C=CC=CC=1)C>[F:1][C:2]([P:4](=[O:11])([O:5][CH2:6][CH3:7])[O:8][CH2:9][CH3:10])([F:3])[CH2:28][CH2:27][O:26][CH2:25][CH2:24][O:23][CH2:22][CH2:21][I:20]To a solution of diethyl difluoromethylphosphonate (1.0 equiv.) in THF (0.8 M) at −78° C. was slowly added a solution of LDA (2 M, 1.1 equiv.) in heptane/THF/ethylbenzene, and the mixture was vigorously stirred for 30 minutes. In a separate reaction flask, a solution of 1,2-bis(2-iodoethoxy)ethane (1.0 equiv.) in THF (0.8M) was cooled to −78° C. To this solution was transferred, by cannula, the freshly prepared alkyl lithium solution and the reaction mixture was allowed to stir for 1 hour at −78° C. At this point, the cooling bath was removed and the reaction mixture was allowed to warm to room temperature. The reaction mixture was then quenched with a 1 M aqueous solution of HCl. The resulting mixture was transferred to a separatory funnel and washed with CH2Cl2 three times. The combined organic layers were dried over anhydrous Na2SO4 and the volatiles were removed in vacuo. The resulting residue was purified by a COMBIFLASH® system (ISCO) using CH2Cl2 to provide diethyl 1,1-difluoro-3-(2-(2-iodoethoxy)ethoxy)propylphosphonate (I-1) as a yellow oil. 1H NMR (CDCl3): δ 4.23-4.31 (m, 4H), 3.75-3.80 (m, 4H), 3.60-3.67 (m, 4H), 3.26 (t, 2H), 2.33-2.50 (m, 2H), 1.38 (t, 6H).
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