(2R,5R)-1-Benzyl 2-Methyl 5-(but-3-en-1-yl)pyrrolidine-1,2-dicarboxylate is an intermediate in the synthesis of (+)-Anatoxin A Hydrochloride (A653360), a secondary, bicyclic amine alkaloid and cyanotoxin with acute neurotoxicity. The toxin is produced by at least four different genera of cyanobacteria and has been reported in North America, Europe, Africa, Asia, and New Zealand. Symptoms of anatoxin exposure are loss of coordination, muscular fasciculations, convulsions and death by respiratory paralysis.