Allyl bromide → 1-Allyl-4-bromo-2-methylbenzene

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 4-bromo-1-iodo-2-methylbenzene (8.41 mL, 58.9 mmol) in THF (200 mL) in a 1.0 L flask under Ar at −20° C., was added isopropylmagnesium chloride (2M, THF) (52.5 mL, 105 mmol) though a dropping funnel. The reaction was stirred for 20 min at −20° C. A solution of lithium chloride (6.00 g, 141 mmol) and copper(I) cyanide (6.33 g, 70.7 mmol) in THF (140 mL) (stirred 15 min at rt to dissolve the LiCl) was cannulated to the above solution. The pale green solution was stirred for 10 min at −10° C., then allyl bromide (15.30 mL, 177 mmol) was added. The mixture was stirred at −10° C. for 30 min. The reaction was quenched with 0.5 N HCl and the solvent was evaporated. The residue was redissolved in diethyl ether/ethylacetate and organic phase was washed with 1N HCl, H2O, brine and dried over sodium sulfate. After evaporation of solvent, the crude product was purified by flash chromatography (0% to 15% EtOAc in hexanes). The desired fractions were combined and concentrated to give 16A (12.10 g, 97% yield). 1H NMR (400 MHz, chloroform-d) δ ppm 7.15-7.25 (m, 2H) 6.92 (d, J=8.24 Hz, 1H) 5.83 (dddd, J=16.97, 10.37, 6.18, 6.05 Hz, 1H) 5.00 (d, J=9.89 Hz, 1H) 4.85-4.94 (m, 1H) 3.23 (d, J=6.60 Hz, 2H) 2.18 (s, 3H).

Herkunft & Nachweise