Synthesis of two alnustone-like natural diarylheptanoids via 4+3 strategy

The first total synthesis of (4E,6E)-1,7-bis(3,4-dihydroxyphenyl)-hepta-4, 6-dien-3-one and an alternative synthesis of (4E,6E)-1,7-bis(4-hydroxyphenyl)- hepta-4,6-dien-3-one, two natural diarylheptanoids, mainly based on Claisen-Schmidt condensation were described. The crucial steps of the syntheses were the condensation of OH-protected 4-aryl-2-butanones with OH-protected 3-aryl-acrylaldehydes by the in situ enamination and then deprotection of OH groups to give the corresponding natural diarylheptanoids.