Multiple hydride reduction pathways in isoflavonoids

BACKGROUND Isoflavonoids are of interest owing to their appearance in metabolic pathways of isoflavones, and their estrogenic and other physiological properties, making them promising lead compounds for drug design. RESULTS The reduction of isoflavones by various hydride reagents occurs by a 1,4-pathway in contrast to ordinary beta-alkoxy-alpha,beta-unsaturated ketones. Isoflavan-4-ones, cis- and trans-isoflavan-4-ols, alpha-methyldeoxybenzoins or 1,2-diphenylprop-2-en-1-ols are obtained depending on the hydride reagent, mostly in good yields. The stereoselective reduction of isoflavan-4-ones is also discussed. CONCLUSION The work described in this paper shows that most structural types of reduced isoflavonoids are now reliably available in satisfactory or good yields by hydride reductions to be used as authentic reference compounds in analytical and biological studies.