| Abstract | Acetylenic acids are isomerized by alkali metal amides of 1,3-diaminopropane to 3,5-dienoic acids. An acid with a methyl branch at C-3 separating the carboxyl from the triple bond is rearranged to a mixture of the terminal alkynoic acid and two isomeric 3,5-dienoic acids. The corresponding 4-methyl compound affords the terminal alkynoic acid, one 3,5-dienoic acid, and two cyclized products, cis- and trans-3-methyl-5-(octylidene)-1-cyclopentanecarboxylic acids. Propargylic acids branched at C-5 and C-6 are rearranged to the appropriately substituted 3,5-dienoic acids in moderate yield. |
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