4-Bromotoluene → AGN 193109 Ethyl Ester

Participants

Reaction Steps

A solution of 4-lithiotoluene was prepared by the addition of 189.9 mg (1.74 ml, 2.96 mmol) of t-butyl lithium (1.7M solution in hexanes) to a cold solution (−78° C.) of 253.6 mg (1.482 mmol) of 4-bromotoluene in 2.0 ml of THF. After stirring for 30 minutes a solution of 269.4 mg (1.977 mmol) of zinc chloride in 3.0 ml of THF was added. The resulting solution was warmed to room temperature, stirred for 30 minutes, and added via cannula to a solution of 472.9 mg (0.988 mmol) of ethyl 4-[(5,6-dihydro-5,5-dimethyl-8-(trifluoromethylsulfonyl)oxy-2-naphthalenyl)ethynyl]benzoate (Compound G) and 50 mg (0.04 mmol) of tetrakis(triphenylphosphine)palladium(0) in 4.0 ml of THF. The resulting solution was heated at 50° C. for 45 minutes, cooled to room temperature and diluted with sat. aqueous NH4Cl. The mixture was extracted with EtOAc (40 ml) and the combined organic layers were washed with water and brine. The organic phase was dried over Na2SO4 and concentrated in vacuo to a yellow oil. Purification by column chromatography (silica, 5% EtOAc-hexanes) yielded the title compound as a colorless solid. 1H NMR (d6-acetone): δ 1.35 (6H, s), 1.40 (3H, t, J=7.1 Hz), 2.36 (2H, d, J=4.7 Hz), 2.42 (3H, s), 4.38 (2H, q, J=7.1 Hz), 5.99 (1H, t, J=4.7 Hz), 7.25 (5H, m), 7.35 (2H, m), 7.52 (2H, d, J=8.5 Hz), 7.98 (2H, d, J=8.5 Hz).

Provenance & Evidence