Synthesis of 3-alkenyl-2-arylchromones and 2,3-dialkenylchromones via acid-catalysed retro-Michael ring opening of 3-acylchroman-4-ones
摘要:
3-Acylchromones and 3-acylflavones, readily available by acylation of 2'-hydroxydibenzoylmethane with acid anhydrides in the presence of base, undergo efficient conjugate reduction with NaBH4 in pyridine to give the corresponding chroman-4-ones/flavanones in high yields. The reduction is both regio- and chemoselective. Treatment of the chroman-4-ones with MeSO3H generates the 3-alkenyl-2-arylchromones by a dehydrative rearrangement initiated by retro-Michael cleavage of the pyranone ring. This reduction-rearrangement sequence can be extended to 2-alkyl-3-alkenoylchromones to generate 3-alkenyl-2-styrylchromones, the first examples of 2,3-dialkenylchromones. (c) 2005 Elsevier Ltd. All rights reserved.
Synthesis of Multi-Functionalized Chromeno[2,3-c]pyrrol-9(2H)-ones: Investigation and Application of Baker-Venkataraman Rearrangement Involved Reactions Catalyzed by 4-(Dimethylamino)pyridine
作者:Yanjun Yu、Yun Hu、Weiyan Shao、Jianing Huang、Yinglin Zuo、Yingpeng Huo、Linkun An、Jun Du、Xianzhang Bu
DOI:10.1002/ejoc.201100435
日期:2011.8
An efficient one-potsynthesis of multi-functionalized chromeno[2,3-c]pyrrol-9(2H)-onesfrom 1,3-diaryl-1,3-diketones and amino acids is described. The synthesis is based on the 4-(dimethylamino)pyridine-catalyzed Baker–Venkataraman rearrangement and subsequent reactions.