Imidazole → (R)-Methyl 2-((tert-butoxycarbonyl)amino)-3-((tert-butyldimethylsilyl)oxy)propanoate

참여 물질

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To a solution of (R)-methyl 2-(tert-butoxycarbonylamino)-3-hydroxypropanoate (27.5 g, 0.126 mol) in DMF (250 mL) was added imidazole (25.7 g, 0.378 mol), followed by TBSCl (20.9 g, 0.139 mol) and the reaction mixture stirred for 4 h. The solvents were removed in vacuo and dissolved in EtOAc (300 mL). The solution was washed with saturated NH4Cl (2×100 mL), then with saturated NaHCO3 (100 mL), and brine (100 mL). The organic layer was then dried, filtered, and solvent removed in vacuo to give (R)-methyl 2,2,3,3,10,10-hexamethyl-8-oxo-4,9-dioxa-7-aza-3-silaundecane-6-carboxylate (40 g, yield 95%) as an oil that was used in the next step without further purification. 1H NMR (CDCl3, 400 MHz) δ 5.34 (brs, 1H), 4.35 (m, 1H), 4.05 (dd, J=13.2, 3.6 Hz, 1H), 3.82 (dd, J=14, 4.4 Hz, 1H), 1.45 (s, 9H), 3.73 (s, 3H), 0.86 (s, 9H), 0.02 (s, 6H).

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