tert-butyl(1S)-1-[(2S)-5-oxotetrahydrofuran-2-yl]-2-phenylethylcarbamate → (5S)-5-[(1S)-1-(N-t-butoxycarbonylamino)-2-cyclohexylethyl]dihydrofuran-2(3H)-one

Participants

Reaction Steps

15 g (49.12 mmol) of 5(S)-[1(S)-(Boc-amino)-2-phenylethyl]dihydrofuran-2-(3H)-one [Example 2b)] are dissolved in 150 ml of methanol, and this solution is treated with 0.75 g of Nishimura catalyst and hydrogenated (RT, standard pressure) until there is no further uptake of hydrogen. The catalyst is filtered off, the solvent is removed, and the residue is chromatographed on silica gel (toluene/ethyl acetate, 5:1). The title compound is obtained as a thick, viscous oil. IR (CH2Cl2) inter alia: 3431, 1774, 1711, 1501 und 1170 cm-1. FAB-MS (M+1)+ =312. 1H-NMR (DMSO-d6) inter alia: 6.80 (d, 1H); 4.40 (m, 1H); 3.66 (m, 1H); 2.58-2.43 (m, 2H); 2.37 (dxq, 1H); 2.14 (m, 1H) and 1.39 (s, 9H).

Provenance & Evidence