On the biosynthesis and optical activity of the flinderoles

A proposed biosynthesis of the flinderoles described herein would produce racemic compounds through nonenzymatic dimerization of borrerine. However, an initial report of optical activity for natural flinderoles is inconsistent with that hypothesis as well as the racemic production of similar natural products. Herein, pure enantiomers of flinderole B were obtained and the specific rotations thereof were found to be significantly different from those in the original report, which were taken at low concentrations. These new data remove the inconsistency arising from the original data.