1,8-Diazabicyclo(5.4.0)undec-7-ene → 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

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Reaction Steps

(R)-2-[4-(3,4-Dichloro-benzyloxy)-phenyl]-2,3-dihydro-benzo[1,4]dioxine-6-carbaldehyde (5.0 g) was dissolved in 25 mL dry DCM under nitrogen at rt and 3.6 mL DBU was added by syringe. 3.8 g of Boc-phosphonoglycine trimethyl ester in 10 mL dry DCM was added by syringe dropwise and the mixture stirred at rt for 14 hours. The residue was purified over silica (hexanes to 8:2 hexanes/EtOAc) 4.9 g desired product after drying under vacuum. 1H NMR (400 MHz, CDCl3): 7.54 (d, 1H), 7.46 (d, 1H), 7.35 (m, 2H), 7.27 (m, 1H), 7.22-7.19 (m, 2H), 7.11 (m, 1H), 6.98 (m, 2H), 6.93 (d, 1H), 5.10 (m, 1H), 5.04 (s, 2H), 4.32 (m, 1H), 4.02 (m, 1H), 3.84 (s, 3H), 1.44 (s, 9H).

Provenance & Evidence