Allyl bromide → HCID 69035584, compound

Participants

Reaction Conditions

Reaction Steps

Diisopropylamine (1.74 mL, 12.5 mmol) was dissolved in THF (6.2 mL) under a nitrogen atmosphere and cooled to −78° C. A solution of n-BuLi (2.5 M in hexanes, 5.3 mL) was added dropwise, keeping the temperature below −67° C. The reaction was warmed to −15° C. for 15 min, then cooled back down to −78° C. A solution of 3-[2-(3-trifluoromethylphenyl)-[1,3]dioxolan-2-yl]propionic acid methyl ester (2.71 g, 8.90 mmol) in THF (1.5 mL) was added and the mixture was stirred for 40 min. Allyl bromide (0.92 mL, 11 mmol) and HMPA (0.46 mL, 2.7 mmol) were added simultan-eously and the reaction was stirred at room temperature overnight. The mixture was diluted with EtOAc (400 mL), washed with saturated NH4Cl (3×150 mL), water (2×150 mL), and brine (200 mL), dried over Na2SO4, filtered, and evaporated. The residue was purified by CombiFlash chromatography (silica, 0–40% ether/heptane) to give 2-[2-(3-trifluoromethylphenyl)-[1,3]dioxolan-2-ylmethyl]pent-4-enoic acid methyl ester (1.82 g, 59%) as a light yellow oil: 1H NMR (300 MHz, CDCl3) δ 7.73 (s, 1H), 7.64 (d, J=7.7 Hz, 1H), 7.56 (d, J=7.7 Hz, 1H), 7.46 (t, J=7.7 Hz, 1H), 5.80–5.61 (m, 1H), 5.10–4.97 (m, 2H), 4.10–3.90 (m, 2H), 3.80–3.60 (m, 5H), 2.83–2.68 (m, 1H), 2.50–2.13 (m, 3H), 1.97 (dd, J=14.7, 2.7 Hz, 1H); 19F NMR (282 MHz, CDCl3) δ −62.9; ESI MS m/z 345 [C17H19F3O4+H]+.

Provenance & Evidence