Total Syntheses of (-)-α-Kainic Acid

Kainoid amino acids are a unique group of non-proteinogenic pyrrolidinedicarboxylic acids. The parent member, ()-a-kainic acid (originally known as digenic acid), has attracted considerable interest, largely because of its neuroexcitatory properties, as well as its pronounced insecticidal and anthelmitic activities. Because these activities are strongly due to its stereochemistry, ()-a-kainic acid represents a considerable synthetic challenge, and many groups have therefore reported syntheses of kainic acids, as well as of kainoid analogues. This article is intended to review the total synthesis of kainic acid from 1996 until the end of 2011.