An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenone derivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of both the double bond and the ketone using NaBH4 and an acetic acid mediated cyclization. Methoxy groups on the aromatic rings did not affect significantly the yields of the procedure.
Mazimba, O., Masesane, I. B., & Majinda, R. R. (2011). An efficient synthesis of flavans from salicylaldehyde and acetophenone derivatives. Tetrahedron Letters, 52(50), 6716-6718. https://doi.org/10.1016/j.tetlet.2011.09.147