Synthesis of 3-(2-Olefinbenzyl)-4<i>H</i>-chromen-4-one through Cyclobenzylation and Catalytic C–H Bond Functionalization Using Palladium(II)
作者:Yu-Feng Lin、Chi Fong、Wan-Ling Peng、Kuei-Chien Tang、Yi-En Liang、Wen-Tai Li
DOI:10.1021/acs.joc.7b01626
日期:2017.10.20
and benzyl bromide to produce homoisoflavonoid. The second step involves intermolecular Pd-catalyzed π-chelating-assisted C–H bond olefination. Using the C-2/C-3 double bond of chromone, palladium-catalyzed aryl C–H bond activation can be functionalized to generate ortho-olefination derivatives in moderate to high yields.
开发了一种有效的策略,可以分两步合成3-(2-烯烃苄基)-4 H -chromen -4-one。第一步是(E)-3-(二甲基氨基)-1-(2-羟基苯基)丙-2-烯-1-酮与苄基溴之间的环苄基化反应,以生成均异黄酮。第二步涉及分子间Pd催化的π螯合辅助的C–H键烯化。使用色酮的C-2 / C-3双键,可以将钯催化的芳基C–H键活化功能化,以中等至高收率生成邻烯化衍生物。
Reactivity of α-arylidene benzoheteracyclanone dibromides toward azide ion: an effective approach to 3-(α-substituted-benzyl)chromones and -1-thiochromones
dibromides of 3-arylidenechromanones and -1-thiochromanones with sodium azide resulted in the formation of 3-(α-azidobenzyl)chromones and -1-thiochromones whereas dibromides having no antiperiplanar vicinal hydrogen in the ring such as flavanone, 1-thioflavanone and benzosuberone derivatives afforded only the parent enones by bromine elimination. Evidence supported the intermediacy of 3-(α-bromobenzyl)chromones
comparative study of the epoxidation of homoisoflavones (3-benzyl-4-chromones) 1–4 has been performed by various oxidizing agents, víz. Epoxidation with isolated dimethyldioxirane (Method A), with alkaline hydrogen peroxide (Method B), and with sodium hypochlorite (Method C) to obtain the epoxides 4–8. Compounds 2 and 3 have also been oxidized with a combination of dimethyldioxirane and Jacobsen's Mn(III)salen
Synthesis of Pyrazoles by Treatment of 3-Benzylchromones, 3-Benzylflavones and Their 4-Thio Analogues with Hydrazine
作者:Albert Lévai、Artur M. S. Silva、José A. S. Cavaleiro、Ibon Alkorta、José Elguero、József Jekő
DOI:10.1002/ejoc.200600043
日期:2006.6
The synthesis of pyrazoles 13–24 has been accomplished by treatment of 3-benzylchromones 1–5, 3-benzylflavones 6–12 and their 4-thioanalogues 25–29 with hydrazine hydrate in hot pyridine. A plausible reaction mechanism for the formation of pyrazoles 13–24 is discussed. A 1H NMR study in [D6]DMSO allowed the presence of both pyrazole annular tautomers to be observed, due to the presence of intramolecular
Palladium-Catalyzed Double-Bond Migration in the Homoisoflavone System
作者:Yukio Hoshino、Noboru Takeno
DOI:10.1246/bcsj.67.2873
日期:1994.10
3-Benzylidene-4-chromanones were converted to 3-benzylchromones in HMPA at 200 °C in excellent yields. The reaction was irreversible and efficiently promoted by palladium catalysts in a remarkably shortened reaction time (3 h), compared with the existing procedure (24 h).
3-亚苄基-4-色满酮在 HMPA 中于 200 °C 转化为 3-苄基色酮,收率极佳。与现有程序(24小时)相比,该反应是不可逆的,并通过钯催化剂有效促进,反应时间显着缩短(3小时)。