Reaction Steps
To a solution of tert-butyl 2-(2,2-dimethylchroman-6-sulfonamido)acetate (20 mg, 0.056 mmol) in acetonitrile (1 mL) was added 3-(bromomethyl)biphenyl (19.47 mg, 0.079 mmol) and resin-supportedBEMP (42.9 mg, 0.084 mmol). The mixture was heated in an oil bath at 90° C. overnight. The reaction mixture was filtered, and the filtrate was concentrated to give an orange residue, which was purified by preparative HPLC using MeCN—H2O-0.1% TFA as the solvent to obtain tert-butyl 2-(N-(biphenyl-3-ylmethyl)-2,2-dimethylchroman-6-sulfonamido)acetate as an oil (26 mg, 84% yield). 1H NMR (500 MHz, CDCl3) δ 7.64-7.60 (m, 2H), 7.54-7.49 (m, 3H), 7.44-7.40 (m, 3H), 7.38 (dd, J=9.4, 5.8 Hz, 1H), 7.33 (ddd, J=6.7, 4.0, 1.2 Hz, 1H), 7.22 (d, J=7.7 Hz, 1H), 4.57 (s, 2H), 3.84 (s, 2H), 2.78 (t, J=6.7 Hz, 2H), 1.80 (t, J=6.7LRMS [ESI, MNa+] m/z calcd for C30H35NO5SNa 544.21. found 544.32. To the solution of tert-butyl 2-(N-(biphenyl-3-ylmethyl)-2,2-dimethylchroman-6-sulfonamido)acetate (23 mg, 0.044 mmol) in DCM (1 mL) was added trifluoroacetic acid (0.102 mL, 1.323 mmol). The mixture was stirred at RT for 1 hour. The reaction mixture was concentrated to give a reddish residue, which was purified by preparative HPLC using MeCN—H2O-0.1% TFA as the solvent to obtain the product as a white powder (17 mg, 82% yield). 1H NMR (500 MHz, CDCl3) δ 7.61 (d, J=6.3 Hz, 1H), 7.60 (s, 1H), 7.51 (d, 1H), 7.50 (d, J=7.4 Hz, 2H), 7.41 (dd, J=13.4, 5.5 Hz, 2H), 7.39 (s, 1H), 7.36 (d, J=7.7 Hz, 1H), 7.34 (t, J=7.3 Hz, 1H), 7.19 (d, J=7.6 Hz, 1H), 6.87-6.83 (m, 1H), 4.52 (s, 2H), 3.97 (s, 2H), 2.77 (t, J=6.7 Hz, 2H), 1.79 (t, J=6.7 Hz, 2H), 1.33 (s, 6H). LRMS [ESI, (M−H)−] m/z calcd for C26H26NO5S 464.15, found 464.32.
