Total synthesis of (–)-α-kainic acid

N-Alkylation of the β-amino acid derivative 16, derived from (L)-aspartic acid, by the allylic chloride 12b followed by deprotection and lactonization leads to the nine-membered azalactone 18. Enolate Claisen rearrangement of this leads stereospecifically, via a boat-like transition state (cf. 6), to the pyrrolidine acid 19; subsequent one-carbon homologation, oxidation and deprotection affords (–)-(α)-kainic acid 1.