Propiolic Acid → 7-Methyl-7-octen-2-ynoic acid

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Reaction Steps

0.13 Gram (1.85 mmol) propiolic acid is dissolved in 20 ml ether, under nitrogen, and the solution is cooled to -70°. 3.3 Milliliters of 1.1 M t-butyllithium (3.63 mmol) is added over a period of 1 hr, and the mixture is stirred for an additional hour at -60°. HMPA (10 ml) is added, followed by 0.32 g (1.96 mmol) 1-bromo-4-methyl-4-pentene (prepared as in either Example 1 or Example 3), keeping the solution cold. After 24 hr, the mixture is heated to 40°-45°. After 3 days, the reaction is worked up in 5% NaOH/ether, and the aqueous layer is extracted with ether. The basic phase is acidified with HCl and extracted with ether (2×). The latter ether phases are washed with water and brine, dried over Na2SO4, filtered and the solvent is removed to yield 7-methyl-7-octen-2-ynoic acid.

Provenance & Evidence