Phosphorous Acid Promoted Hydration–Condensation of Aromatic Alkynes with Aldehydes Affording Chalcones in an Oil/Water Two-Phase System
摘要:
A simple and environmentally benign method was developed for the synthesis of chalcones in high to excellent yields by a phosphorous acid promoted alkyne-aldehyde hydration-condensation in an oil/water two-phase system. The method is the first efficient protocol for the preparation of chalcones that is mediated by a simple BrOnsted acid in a two-phase system.
Copper complexes of phosphoramidites efficiently catalyzed asymmetricaddition of arylboron reagents to acyclic enones. Importantly, rare 1,4-insertion of arylcopper(I) was identified which led directly to O-bound copper enolates. The new mechanism is fundamentally different from classical oxidative addition/reductive elimination of organocopper(I) on enones.
亚磷酰胺的铜配合物有效地催化芳基硼试剂向无环烯酮的不对称加成。重要的是,鉴定了稀有的芳基铜(I)的 1,4-插入,这直接导致了与 O 结合的铜烯醇化物。新机制与传统的有机铜(I)在烯酮上的氧化加成/还原消除有着根本的不同。
Alkylation of Indoles with α,β‐Unsaturated Ketones using Alumina in Hexanes
We evaluated the influence of solvent on the alumina‐promoted C3‐alkylation of indoles with α,β‐unsaturatedketones. We found that lipophilic solvents were generally superior to hydrophilic ones with hexanes offering the 3‐alkyl indole products in high yields. Thus, we demonstrate an inexpensive and procedurally simple new process that pairs acidic alumina with hexanes to achieve this important Michael
a carbon-centered radicalintermediate, which will overcome side reactions during the styrene radical functionalization process. Experimental studies have provided evidence indicating a domino-fluorination–protodefluorination pathway with α-keto acid initiating the photoredox cycle. The present catalytic protocol also affords a novel approach for the construction of α,β-unsaturated ketones under mild
Syntheses and biological activity of chalcones-imidazole derivatives
作者:Yu-Ting Liu、Xiao-Ming Sun、Da-Wei Yin、Fang Yuan
DOI:10.1007/s11164-012-0665-z
日期:2013.3
A number of novel 13-membered chalcone-imidazole derivatives were prepared and have been synthesized and characterized by IR, 1H NMR, 13C NMR and elemental analysis, the results conformed well to expected structures. Substituted acetophenones and benzaldehydes were condensed using the Claisen–Schmidt base-catalyzed aldol condensation. Methyl on the aromatic ring of chalcones was brominated by NBS, and then the resulting mixture was reacted with imidazole to get the target compound. Several chalcones showed in vitro antibacterial activity against Gram-bacterial. The results showed that these are potential antibacterial compounds.
Trimethylsilyl-1,3,4-oxadiazoles—new useful synthons for the synthesis of various 2,5-disubstituted-1,3,4-oxadiazoles
作者:Evgenij V. Zarudnitskii、Igor I. Pervak、Anatolij S. Merkulov、Aleksandr A. Yurchenko、Andrej A. Tolmachev
DOI:10.1016/j.tet.2008.08.040
日期:2008.11
The reactivity of 2-aryl-5-trimethylsilyl-1,3,4-oxadiazoles toward different types of electrophiles was investigated. These silanes readily react with chlorine, bromine, aliphatic acyl chlorides, 2-nitrobenzenesulfenyl chloride, and somereactive isocyanates affording the corresponding substituted 1,3,4-oxadiazoles. The reactions with carbonylcompounds proceed only in the presence of F− anions.