Toluene → methyl 2-(2-bromo-E-ethenyl)-delta-oxobenzenepentanoate

Participants

Reaction Conditions

Reaction Steps

To 10ml of toluene was added 6.0g (9.9 mol) of trans-1,2-bis(tri-n-butylstannyl)ethylene, which was prepared according to the procedure of Corey, et al., J. Org. Chem., 40, 3788 (1975), and 0.5g (1.8 mmol) of the product of Example 3. To the solution was then added 0.040g (.035 mmol) of 2 mole% tetrakis(triphenylphosphine)palladium(O) and the solution was degassed with argon. The reaction mixture was heated under argon for 1 hour at 120°C. (oil bath). Thereafter, the reaction mixture was cooled to -20°C. To the reaction mixture was added dropwise with stirring, a solution of 1.5ml (29.1 mmol) of Br2 in 30ml of CCl4 until thin layer chromatography of the reaction mixture indicated that all of the product of Example 3 was consumed. The volatile components were removed in vacuo. The residue was flash chromatographed on a silica gel column. Sequential elution with hexane, 5% diethyl ether in hexane, and 10% diethyl ether in hexane produced 0.48g of the titled product. The product was triturated with cold hexame to give a white solid, m.p. 52-55°C.

Provenance & Evidence