反应详情

3-[4-tert-Butoxy-1,4-dioxo-2(R)-(4-thiazolylmethyl)butyl]-4(S)-(1-methylethyl)-2oxazolidinone: The product of section (a) of this example (825 mg, 3.07 mmol) was stereoselectively alkylated with tert-butyl 2-bromoacetate according to the procedure described in example 2, section (f) to give a mixture of the desired 3-[4-tert-butoxy-1,4-dioxo-2(R)-(4-thiazolylmethyl)butyl ]-4(S)-(1-methylethyl)-2-oxazolidinone (Rf=0.25, eluent: EtOAc-hexane, 1:2) and its corresponding 2(S)-epimer (Rf=0.41, eluent: EtOAc-hexane, 1:2) in a 7:1 ratio, respectively. Flash chromatography (SiO2, eluent: EtOAc-hexane, 1:2) yielded the pure desired compound as a white solid (882 mg, 75%), 1H NMR(CDCl3) δ 8.75 (S,1H), 7.14 (s,1H), 4.62-4.5 (m, 1H), 4.50-4.40 (m, 1H), 4.29-4.20 (m,2H), 3.19 (dd, J=6.4 Hz,14.2 Hz,1H), 3.02 (dd, J=7.5 Hz,14.2 Hz,1H), 2.84 (dd, J=9.8 Hz,16.6 Hz,1H), 2.49 (dd, J=4.7 j Hz,16.6 Hz,1H), 1.41 (s,9H), 0.95 (d, J=6.8 Hz,3H), 0.92 (d, J=7.0 Hz,3H).

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