First total synthesis of two nematicidal prenylated flavanones

The total synthesis of (+/-)-8-(3-methylbut-2-enyl)-2-phenyl-2,3-dihydrochromen-4-one and (+/-)-2-(4-hydroxyphenyl)-8-(3-methylbut-2-enyl)-2,3-dihydrochromen-4-one was first achieved through C-prenylation, protection of phenolic hydroxyl group, aldol condensation, cyclization and deprotection. starting from cheap benzaldehyde, 4-hydroxybenzaldehyde and 2-hydroxyacetophenone, with total yield of 20 and 16.3%. All structures of new compounds were confirmed by IR, (1)H NMR and MS. (C) 2009 Jin Hui Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.