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Journal of Chemistry
Volume 2017, Article ID 3971253, 11 pages
Research Article

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

1Faculty of Natural Sciences, Mangosuthu University of Technology, Umlazi, Durban, KwaZulu-Natal, South Africa
2Department of Agriculture, Faculty of Health and Environmental Sciences, Central University of Technology, Free State, 1 Park Road, Bloemfontein 9301, South Africa

Correspondence should be addressed to Matthew Chilaka Achilonu;

Received 21 December 2016; Accepted 7 March 2017; Published 18 May 2017

Academic Editor: Bin Yu

Copyright © 2017 Matthew Chilaka Achilonu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.