First Synthesis of (±)-C-3-Prenylated Flavanones

Abstract 2,4,6-tris(Methoxymethoxy)acetophenone (1) was first mono-alkylated with 3-methylbut-2-enyl bromide to yield 5-methyl-1-(2,4,6-trimethoxymethoxyphenyl)hex-4-en-1-one (2). The base catalyzed aldol condensation of 2 and substituted benzaldehydes gave chalcones 3 in good yields. One pot cyclization and deprotection of the chalcones were accomplished in refluxing 4 N HCl in MeOH to afford (±)-C-3-prenylated flavanones.