Total Synthesis and Determination of the Stereochemistry of 2-Amino-3-cyclopropylbutanoic Acid, a Novel Plant Growth Regulator Isolated from the Mushroom Amanita castanopsidis Hongo.

The unknown stereostructure of 2-amino-3-cyclopropylbutanoic acid 1, a novel plant growth regulator isolated from the mushroom Amanita castanopsidis Hongo, was determined to be (2S,3S)-2 through its racemic and enantioselective syntheses employing the chelate-enolate Claisen rearrangement as a key step.