Synthesis of [2H8]-enterolactone and [2H10]-enterodiol

Enterolactone and enterodiol are the main mammalian metabolites of dietary butyrolactone type lignans. The study of biological properties and potential health effects of these compounds requires isotopically labelled compounds as standards for quantitative measurements. An expedient deutero‐labelling method for enterolactone is to use the D3PO4·BF3/D2O complex at room temperature which will exchange all eight aromatic hydrogens, even from inactivated meta positions, to form [2,4,5,6,2′,4′,5′,6′‐2H8]‐enterolactone in 74% yield and 99% isotopic purity. [2,4,5,6,9,9,2′,4′,5′,6′‐2H10]‐Enterodiol was prepared from [2,4,5,6,2′,4′,5′,6′‐2H8]‐enterolactone by reduction with LiAlD4 which introduces two more deuterium atoms into the molecule. Copyright © 2003 John Wiley & Sons, Ltd.