methyl (2Z)-2-[(benzyloxy)carbonyl]amino-3-[3-bromo-4-(1,1-dioxido-3-oxo-2-[2-(trimethylsilyl)ethoxy]methylisothiazolidin-5-yl)phenyl]acrylate → Methyl (2S)-2-[(benzyloxy)carbonyl]amino-3-[3-bromo-4-(1,1-dioxido-3-oxo-2-[2-(trimethylsilyl)ethoxy]methylisothiazolidin-5-yl)phenyl]propanoate

Participants

Reaction Steps

A solution of methyl (2Z)-2-[(benzyloxy)carbonyl]amino-3-[3-bromo-4-(1,1-dioxido-3-oxo-2-[2-(trimethylsilyl)ethoxy]methylisothiazolidin-5-yl)phenyl]acrylate (0.24 g, 0.37 mmol) in ethanol (10 mL) was bubble with nitrogen. (R,R)-(−)-1,2-bis[(o-methoxyphenyl)(phenyl)phosphino]ethane (1,5-cyclooctadiene) rhodium (I) tetrafluroborate (3 mg, 0.004 mmol) was added to the reaction solution and nitrogen was bubble through. After five cycles of vacuum/H2, the reaction was processed at a H2 pressure of 50 psi at room temperature. After 18 h, the solvent was removed under reduced pressure and the residue was purified with silica gel chromatography (5%–50% ethyl acetate/hexanes) to afford product as a white solid (0.22 g, 91%). 1H NMR (400 MHz, CDCl3): δ 7.47 (dd, J=13.3, 1.4 Hz, 1H), 7.33 (m, 5H), 7.24 (m, 1H), 7.14 (m, 1H), 5.47 (m, 1H), 5.06 (m, 4H), 4.10 (m, 1H), 3.72 (s, 3H), 3.65 (t, J=8.0 Hz, 2H), 3.43 (dd, J=17.5, 8.2 Hz, 1H), 3.18 (m, 2H), 3.04 (dd, J=17.5, 6.4 Hz, 1H), 0.97 (dd, J=8.4, 7.2 Hz, 2H), 0.01 (s, 9H). LCMS found for C27H35BrN2O8SSiNa (M+Na)+: m/z=677, 679.

Provenance & Evidence