Ethyl Bromide → HCID 54757324, compound

Participants

Reaction Conditions

Reaction Steps

n-BuLi (1.6 M in hexanes, 1.0 mL, 1.6 mmol) was added at 0° C. to the flask containing diisopropylamine (262 μL, 1.54 mmol) and THF (2 mL). The solution was stirred at 0° C. for 20 min., cooled to −78° C. and siphoned to the solution of 2 (430 mg, 1.31 mmol) in THF (1.5 mL). The resulted yellow mixture was stirred for 30 min, then HMPA (600 μL) was added and stirring was continued for another 15 min. Then CH3CH2Br (310 μL, 4.08 mmol) was added, and the solution was stirred at −78° C. for 40 min. Saturated NH4Cl was added and the mixture was extracted with ethyl acetate. The combined organic phases were washed with water, dried (MgSO4) and evaporated. The residue was applied on a silica column. Elution with hexane/ethyl acetate (95:5) resulted in pure compound 3 (280 mg, 60%; 80% based on recovered substrate). Further elution with hexane/ethyl acetate (95:5) gave unreacted 2 (107 mg). 3: [α]24D+117.5° (c 0.2 CHCl3); 1H NMR (400 MHz, CDCl3) δ 1.023 (3H, t, J=7.4 Hz, 23-H3), 1.337 (3H, s, 18-H3), 1.397 (3H, s, 21-H3), 2.14 (1H, br d, J=12.9 Hz, 9β-H), 5.40 (1H, narr m, 8α-H), 7.45 (2H, t, J=7.4 Hz, Ar), 7.57 (1H, t, J=7.4 Hz, Ar), 8.05 (2H, d, J=7.4 Hz, Ar).

Provenance & Evidence