1,1,3-Trichlorobut-1-ene → Ethyl 5,5-dichloro-3-methyl-2-propan-2-ylpent-4-enoate

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Reaction Steps

A 250 ml R.B. flask was equipped with a magnetic stirrer, reflux condenser, and N2 inlet tube. The glassware was dried thoroughly then charged with 23.91 g (0.15 mol) of 1,1,3-trichloro-1-butene, 30.36 g (0.15 mol) of 1-trimethylsilyloxy-1-ethoxy-3-methyl-1-butene, 100 ml of methylene chloride, and ~0.50 g of anhydrous zinc chloride. The reaction mixture was stirred at room temperature and monitored by infrared. The gradual disappearance of the ketene acetal C=C peak at 1675 cm-1 and the appearance of an ester C=O peak at 1720 cm-1 was observed. The reaction mixture after 67 hours showed only a c=O peak at 1720 cm-1 and no 1675 cm-1, and was diluted with 150 ml of methylene chloride, washed with 5×100 ml of 5% sodium bicarbonate solution, then 2×with 50 ml of water. The methylene chloride was dried (MgSO4), stripped, and the residue vacuum distilled through a vigreux column to give 23.41 g (62% yield) of the desired product, b.p. 64°-68° C./0.30 mm.

Provenance & Evidence