1,4-Dibromobutane → Ethyl 6-bromo-2-methyl-2-phenylhexanoate

Beteiligte Stoffe

Reaktionsschritte

A solution of LDA (14 mL, 28 mmol, 2.0 M in heptane) was added dropwise to a stirred solution of 202 (5.0 g, 28.06 mmol) in anhydrous THF (50 mL) at −78° C. After 1 h, the reaction mixture was added to a −78° C. cold solution of 1,4-dibromobutane (10.06 g, 23.1 mmol) in THF. After the addition of DMPU (5 mL), the reaction mixture was stirred for 1 h, then warmed to room temperature and stirred overnight. The mixture was poured into saturated aqueous NH4Cl solution (500 mL) and extracted with ethyl acetate (4×100 mL). The combined organic phases were washed with brine (100 mL), 1 M HCl (50 mL), saturated aqueous NaHCO3 solution (50 mL), and brine (100 mL). The solution was dried over anhydrous MgSO4 and concentrated in vacuo. The residue was distilled to give 205d as an oil (7.16 g, 99%). Bp 130-131° C./0.2 mm Hg. 1H NMR (CDCl3), δ (ppm): 7.40-7.15 (m, 5 H), 4.13 (q, 2 H, J=6.7), 3.36 (t, 2 H, J=6.7), 2.02 (m, 2 H), 1.86 (m, 2 H), 1.56 (s, 3 H), 1.34 (m, 2 H), 1.18 (t, 3 H, J=6.7). 13C NMR (CDCl3), δ (ppm): 176.13, 143.91, 128.51, 126.81, 126.03, 60.93, 50.22, 38.53, 33.56, 33.30, 23.58, 22.77, 14.22. HRMS (FAB): Calcd for C15H2179BrO2 (MH+): 313.0803, found 313.0786.

Herkunft & Nachweise