2-tert-Butoxycarbonylamino-3-{(R)-2-[4-(3,4-dichloro-benzyloxy)-phenyl]-2,3-dihydro-benzo[1,4]dioxin-6-yl}-acrylic acid methyl ester → (S)-2-tert-Butoxycarbonylamino-3-{(R)-2-[4-(3,4-dichloro-benzyloxy)-phenyl]-2,3-dihydro-benzo[1,4]dioxin-6-yl}-propionic acid methyl ester

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Reaction Steps

2-tert-Butoxycarbonylamino-3-{(R)-2-[4-(3,4-dichloro-benzyloxy)-phenyl]-2,3-dihydro-benzo[1,4]dioxin-6-yl}-acrylic acid methyl ester (4.9 g) was suspended in 300 mL EtOAc. 400 mg (+)-1,2-bis((2S,5S)-2,5-diethylphospholano)benzene(cyclooctadiene)rhodium(I) trifluoromethanesulfonate in 30 mL DCM was added. The mixture was then degassed and a hydrogen balloon was added. The mixture was stirred at room temperature for 2 hours and the solvent was evaporated. The residue was purified by silica gel flash chromatography (hexanes to 8:2 hexanes/EtOAc) to give 4.8 g after drying. 1H NMR (400 MHz, CDCl3): 7.54 (d, 1H), 7.46 (d, 1H), 7.34 (m, 2H), 7.24-7.28 (m, 1H), 6.98 (m, 2H), 6.87 (d, 1H), 6.69 (d, 1H), 6.62 (m, 1H), 5.07-4.96 (m, 4H), 4.54 (m, 1H), 4.30 (m, 1H), 4.0 (m, 1H), 3.74 (s, 3H), 3.0 (m, 2H), 1.43 (s, 9H).

Provenance & Evidence