4-Bromotoluene → Ethyl 4-[(5,6-dihydro-5,5-dimethyl-8-(4-methylphenyl)-2-naphthalenyl)azo]-benzoate

Participants

Reaction Steps

A solution of 4-lithiotoluene was prepared by the addition of 62.9 mg (0.58 ml, 0.98 mmol) of t-butyl lithium (1.7M solution in pentane) to a cold solution (-78° C.) of 84.0 mg (0.491 mmol) of 4-bromotoluene in 1.0 ml of HF. After stirring for 30 minutes a solution of 107.0 mg (0.785 mmol) of zinc chloride in 2.0 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 94.7 mg (0.196 mmol) of ethyl 4-[(5,6-dihydro-5,5-dimethyl-8-(trifluoromethylsulfonyl)oxy-2-naphthalenyl)azo]-benzoate (Compound BB) and 25 mg (0.02 mmol) of tetrakis(triphenylphosphine)palladium(0) in 2.0 ml of THF. The resulting solution was heated at 50° C. for 1.5 hours, 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, concentrated in vacuo, and the title compound isolated as a red solid by column chromatography (25% EtOAc--hexanes) 1H NMR (CDCl3): δ 8.21 (2H, d, J=8.6 Hz), 7.96 (2H, d, J=8.6 Hz), 7.94 (2H, m), 7.49 (1H, d, J=8.2 Hz), 6.08 (1H, t, J 2.5 Hz), 4.42 (2H, q, J=7.1 Hz), 2.49 (2H, d, J=4.8 Hz), 1.44 (3H, t, J=7.1 Hz), 1.38 (6H, s).

Provenance & Evidence