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

Participants

Reaction Conditions

Reaction Steps

To 10 ml of toluene was added 6.0g (9.9 mmol) 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 0.5 g (1.8 mmol) of the product of Example 3. To the solution was then added 0.040 g (0.035 mmol) of 2 mole% tetrakis(triphenylphosphine)palladium(0) 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 1.5 ml (29.1 mmol) of Br2 in 30 ml 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 0.48 g of the titled product. The product was triturated with cold hexane to give a white solid, m.p. 52°-55° C.

Provenance & Evidence