(2R,3R)-Butane-2,3-diol (levo-2,3-Butanediol) is found in cocoa and cocoa products. (2R,3R)-2,3-Butanediol is isolated from cocoa butter and roots of Ruta graveolens (rue).2,3-Butanediol is one of the constitutional isomers of butanediol. The 2R,3R stereoisomer of 2,3-butanediol is produced by a variety of microorganisms, in a process known as butanediol fermentation. It is found in cocoa butter and in the roots of Ruta graveolens.