Allyl bromide → HCID 70087507, compound

Participants

Reaction Steps

Under argon, 1.9 ml of a 1 molar solution of lithium bis-(trimethylsilyl)-amide in THF are added dropwise to a solution, cooled to −78° C., of 0.5 g (1.88 mmol) of the compound from Example 1 in 20 ml of THF such that the temp. of the mixture does not exceed −65° C. After the addition has ended, stirring is continued at −78° C. for 10 min, and 0.26 g (2.25 mmol) of allyl bromide are then added in one portion. Immediately afterwards, the cooling bath is removed and the mixture is allowed to warm to room temp. After 16 h of stirring at room temp., the mixture is taken up in ammonium chloride solution and ethyl acetate and the aqueous phase is extracted twice with ethyl acetate. The combined organic phases are dried over sodium sulphate and then concentrated. The residue was chromatographed over silica gel (mobile phase: dichloromethane). Yield: 255 mg (44%) of a colourless oil. 1H-NMR (200 MHz; CDCl3) δ[ppm]=1.55-2.2 (br m,6H), 2.3 (m, 2H), 2.61 (m,1H), 3.12 (d,1H), 3.3 (d,1H), 4.91 (m,1H), 5.05 (dd,1H), 5.11 (dd, 1H), 5.8 (ddt,1H), 7.35-7.5 (br m,3H), 7.72 (s,1H), 7.80 (m,3H). Diastereomeric purity: >99% de (HPLC).

Provenance & Evidence