Synthesis of α-kainic acid in accordance with the synthetic procedures for α-dihydro-kainic acid described in the proceeding paper* was attempted and the pyrrolidine compounds (XIV-i and -ii) were first prepared through the piperidone compound (VIII). Ethyl 2-cyano-3-methyl-4-ethoxybutyrate (I) was saponified to the carboxylic acid (II), derived to the acid chloride (III), and condensed with diethyl malonate to form but-yroylmalonate compound (IV). Its decarboxylation gave the butyroylacetate compound (V), which was reduced to the hydroxypiperidone compound (VI), treated with aceticanhydride to form the dihydropyridone compound (VII), and submitted to the Michael condensation with diethyl malonate to obtain (VIII). Saponification of (VIII) gave the half ester (IX-i and -ii), dicarboxylic acid (X-i), (X-ii). (X-i and -ii) was derived to monocarboxylic acid (XI-i and -ii) and the dibromo compound (XV-i and -ii). The isomers of (IX) and (X) are stereoisomers arising from the carbon bonded with the ethoxymethyl group, and the configuration of the side chain at C4-C5 position in the compounds was assumed to be in trans. (VIII) was then brominated, the bromo compound (XII) obtained was treated with an excess of alkali, and (XIV-i and -ii) were obtained. Saponification of (XII) with 2 moles of alkali afforded the bromomonocarboxylic acid compound (XIII-ii) which was derived to (XIV-ii). From the comparison of the yields of (XIV-i) and (XIV-ii) with that of the isopropyl compound, (XIV-i) was found to be the chief product.
