Centrocerus clavulatum

Thus, (2R)-pumiliotoxin C (214) has been prepared from (R)-norvaline (212). The asymmetric center in the triene (213) controls the configuration at three carbon atoms 210). a-Kainic acid, isolated from the algae Digena simplex and Centrocerus clavulatum, was prepared by total synthesis. Its enantioselective synthesis involved a stereocon trolled intramolecular cycloaddition of a (S)-glutamic acid211). Asymmetric cycloadditions also play a decisive role in the synthesis of chiral cytochalasins. In this case 212> the primary chiral information was carried by (S)-alanine and (S)-phenylalanine, respectively. 

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