Acetic Acid → (2-{-4-[6-Methoxy-7-methyl-3-oxo-4-(2-trimethylsilanyl-ethoxy)-1,3-dihydro-isobenzofuran-5-yl]-2-methyl-but-2-enylamino}-ethyl)-phosphonic acid diethyl ester

Participants

Reaction Steps

To a solution of 4-[6-methoxy-7-methyl-3-oxo-4-(2-trimethylsilanyl-ethoxy)-1,3-dihydro-isobenzofuran-5-yl]-2-methyl-but-2-enal (84 mg, 0.22 mmol), (2-amino-ethyl)-phosphonic acid diethyl ester oxalate (91 mg, 0.33 mmol), and sodium triacetoxyborohydride (93 mg, 0.44 mmol) in DMF (1.5 mL) was added acetic acid (60 μL, 1.0 mmol) at room temperature. The solution was stirred for 2 days when it was quenched by addition of saturated aqueous sodium bicarbonate solution and EtOAc. The organic layer was separated and concentrated under reduced pressure. The residue was purified by RP HPLC using a C18 column with a gradient of H2O, 0.1% TFA-acetonitrile, 0.1% TFA to provide 115 mg (96%) of the product as an oil. 1H NMR (300 MHz, CDCl3) δ 0.04 (s, 9H), 1.16-1.27 (m, 2H), 1.34 (t, 6H, J=7 Hz), 1.94 (s, 3H), 2.18 (s, 3H), 2.20-2.31 (m, 2H), 3.13-3.31 (m, 2H), 3.48 (d, 2H, J=7 Hz), 3.54 (s, 2H), 3.78 (s, 3H), 4.14 (pent, 4H, J=7 Hz), 4.30-4.37 (m, 2H), 5.13 (s, 2H), 5.65 (t, 1H, J=7 Hz), 6.23 (br s, 2H) ppm; 31P (121.4 MHz, CDCl3) δ 27.8 ppm; MS (m/z) 542.3 [M+H]+, 564.2 [M+Na]+.

Provenance & Evidence