Triphenylphosphine → 4-((4-Bromo-3-chlorophenoxy)methyl)-5-cyclopropyl-3-(2,6-dichlorophenyl)-isoxazole

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Reaction Steps

3-Chloro-4-bromophenol (3.8 g, 18.3 mmol) was mixed with (5-cyclopropyl-3-(2,6-dichlorophenyl)isoxazol-4-yl)methanol (3.47 g, 12.2 mmol) and triphenylphosphine (6.41 g, 24.4 mmol) in toluene (150 mL). The mixture was cooled in an ice-bath and DIAD (4.8 mL, 24.4 mmol) as a solution in toluene (10 mL) was added drop-wise. The reaction was stirred at rt for 21 h and the solvents were removed on a rotavap leaving a yellow oily residue. This was dissolved in DCM (200 mL), silica (˜20 g) was added and the mixture was evaporated to dryness. This material was loaded on the top of a silica column and purified eluting with hexanes/MTBE 9:1. The product containing fractions were pooled and the solvent removed under reduced pressure, leaving pure product 8e as a colourless oil that crystallized upon drying under vacuum overnight. Yield: 5.07 g (88%). 1H-NMR (CDCl3), δ (ppm): 7.45-7.30 (m, 4H), 6.90 (s, 1H), 6.60-6.55 (m, 1H), 2.15-2.07 (m, 1H), 1.32-1.25 (m, 2H), 1.20-1.11 (m, 2H).

Provenance & Evidence