反应详情

To a solution of product from step C (2.00 g, 9.17 mmol) in dichloromethane (25 ml) was added 3-methoxycarbonylbenzyltriphenylphosphonium bromide (4.50 g, 9.17 mmol) and potassium tert-butoxide (1.03 g, 9.17 mmol). The mixture was stirred at room temperature for 18 hrs. A further portion of the phosphonium salt (0.88 g, 1.83 mmol) and potassium tert-butoxide (0.21 g, 1.83 mmol) was added. After 16 hrs at room temperature the mixture was partitioned between brine (50 ml) and dichloromethane (50 ml). The organic phase was washed with brine (2×50 ml) and dried (MgSO4). Evaporation of the solvent left an orange gum which was purified by column chromatography on SiO2 (Merck 9385) eluting EtOAc/ammonia (1%) to give methyl 3-[2-(4-fluorophenyl)-4-(imidazol-1-yl)-but-1-enyl]-benzoate as Z isomer 0.57 g (18%), E isomer 0.38 g (12%) and a mixture of isomers 0.65 g (20%) as a yellow gum.

1. customAfter 16 hrs at room temperature the mixture was partitioned between brine (50 ml) and dichloromethane (50 ml)
2. washThe organic phase was washed with brine (2×50 ml)
3. dry with materialdried (MgSO4)
4. customEvaporation of the solvent
5. waitleft an orange gum which
6. customwas purified by column chromatography on SiO2 (Merck 9385)
7. washeluting EtOAc/ammonia (1%)