title: Studies on flavans. 1. Facile synthesis of (+/-)-7-hydroxy-3',4'-methylenedioxyflavan and (+/-)-4'-hydroxy-7-methoxyflavan by a BF3.Et2O-mediated pyran cyclization.
abstract: A facile approach for the synthesis of flavans was developed by employing a BF3.Et2O-catalyzed pyran cyclization in an aprotic polar solvent as a key step, by which concise total syntheses of (+/-)-7-hydroxy-3',4'-methylenedioxyflavan (1) and (+/-)-4'-hydroxy-7-methoxyflavan (2), two naturally occurring flavans, were achieved.
authors: National Laboratory of Applied Organic Chemistry & Institute of Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China. liyl@lzu.edu.cn
authors: Y
authors: Y
authors: Li
authors: J
authors: J
authors: Yang
authors: W Z
authors: WZ
authors: Li
authors: L
authors: L
authors: Hou
authors: J
authors: J
authors: Xue
authors: Y
authors: Y
authors: Li
mesh_terms: D003500:Cyclization; D005419:Flavonoids / Q000138:chemical synthesis*; D008956:Models, Chemical
chemical_list: C433580:4'-hydroxy-7-methoxyflavan; C107721:7-hydroxy-3',4'-(methylenedioxy)flavan; D005419:Flavonoids