The C(4) acetoxylated catechin and epicatechin derivatives, 4 and 5, smoothly react with various nucleophiles under Lewis acidic conditions, giving C(4)-elaborated flavan-3-ols. Facile synthesis of dryopteric acid (3) was achieved. © 2002 Elsevier Science Ltd. All rights reserved.
Ohmori, K., Ushimaru, N., & Suzuki, K. (2002). Stereoselective substitution of flavan skeletons: Synthesis of dryopteric acid. Tetrahedron Letters, 43(43), 7753–7756. https://doi.org/10.1016/S0040-4039(02)01826-9