Acetic Anhydride → Ethyl 2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)hex-5-enoate

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Reaction Steps

A solution of the ethyl 2-(tert-butoxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate (10.0 g, 35 mmol) and dimethylaminopyridine (4.48 g, 35 mmol) in dichloromethane (100 mL) was treated with acetic anhydride and stirred at room temperature overnight. The solution was concentrated and the resulting residue purified using a combiflash system (89 g column, eluting with 20-50% ethyl acetate in heptanes) to give ethyl 2-(acetoxymethyl)-2-(tert-butoxycarbonylamino)hex-5-enoate (10 g, 80%). 1H NMR (CDCl3) δ 5.78-5.68 (m, 1H), 5.55 (bs, 1H), 5.03-4.93 (m, 2H), 4.73 (d, J=11.0 Hz, 1H) 4.32 (d, J=11.0 Hz, 1H,), 4.20 (q, J=7.2 Hz, 2H), 2.36 (m, 1H), 2.07-2.05 (m, 1H), 2.02 (s, 3H), 1.89-1.75 (m, 2H), 1.43 (m, 9H), 1.27 (t, J=7.2 Hz, 3H). MS found for C16H27NO6 m/z[330(M+1)].

Provenance & Evidence