(R)-tert-butyl 2-(6-(3-(benzyloxy)phenylthio)naphthalen-2-yl)-1-(di-tert-butoxyphosphoryloxy)propan-2-ylcarbamate was dissolved in acetic acid (2.0 mL, 0.035 mol) and 10 M hydrogen chloride in water (0.5 mL) and stirred for 1 d. Removal solvent and concentration gave an oil, which was added to water and ether. The aqueous layer was concentrated and purified by preparative HPLC 0.1% TFA water/ACN to give (R)-2-amino-2-(6-(3-(benzyloxy)phenylthio)naphthalen-2-yl)propyl dihydrogen phosphate as a solid (1.1 mg, 4%). LCMS 1.56 496.25 (M+1, 40%), 991.66. HNMR shows quite pure. 1H NMR (400 MHz, MeOD) δ=7.98 (s, 1H), 7.89 (d, J=8.5 Hz, 2H), 7.82 (s, 1H), 7.65 (d, J=6.7 Hz, 1H), 7.43 (d, J=10.4 Hz, 1H), 7.39-7.25 (m, 6H), 7.05-6.95 (m, 3H), 5.06 (s, 2H), 4.29 (dd, J=5.0, 11.0 Hz, 1H), 4.16 (dd, J=5.4, 11.0 Hz, 1H), 1.86 (s, 3H).
