Stereoselective formal synthesis of (؉)-allokainic acid was accomplished starting from L-glutamate by using a thiol-mediated acyl radical cyclization as a key step. The cyclization of a formylalkenoate proceeded in a highly diastereoselective manner to give trans-4,5-disubstituted pyrrolidin-3-one without the production of the cis-isomer. The pyrrolidinone was then converted into the established synthetic intermediate of (؉)-allokainic acid via the iron-catalyzed coupling reaction with an isopropenyl Grignard reagent.

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