Bioactive Phytochemicals: Efficient Synthesis of Optically Active Substituted Flav-3-enes and Flav-3-en-3-o-R Derivatives

The structural core of flavene (2-phenyl-2h-chromene) is commonly found in plant flavonoids,which exhibit a wide range of biological activities and diverse pharmacological profiles (e.g.,antioxidant and anticancer activities). flavonoids have attracted significant interest in medicinal and synthetic chemistry. substituted flav-3-ene 13 was exclusively synthesized by the stereoselective elimination of the o-mesyl moiety on c-3 of 5,7,3′,4′-tetramethoxyflavan-3-mesylate 12 with 1,8-diazabicyclo[5.4.0]undec-7-ene. the reaction of 5,7,3′,4′-tetramethoxyflavan-3-one 15 with ytterbium trifluoromethanesulfonate in methanol afforded a novel 3-o-substituted flav-3-ene derivative (3,5,7,3′,4′-pentamethoxyflav-3-ene) 17. the reduction of 4-(1,3,5-trihydroxybenzene)-5,7,3′,4′-tetra-o-benzylflavan-3-one 19b with hydrogen afforded a new compound: 3-hydroxy-4-(1,3,5-trihydroxybenzene)-5,7,3′,4′-tetrahydroxyflavan-3-en-3-ol 21 in good yield (95%),while the acetylation of 19a and 21 afforded the expected novel flav-3-en-3-acetoxy derivatives 20 (92%) and 22 (90%),respectively. © 2017 matthew chilaka achilonu et al.