4071-84-5Relevant academic research and scientific papers
Activated charcoal-mediated synthesis of chalcones catalyzed by NaOH in water
Tanemura, Kiyoshi,Rohand, Taoufik
, (2021/02/27)
A variety of chalcones were synthesized in good yields by the activated charcoal-mediated aldol reactions between benzaldehydes and acetophenones catalyzed by NaOH in water. 2,6-Bis((E)-benzylidene)cyclohexan-1-ones were prepared by the aldol reactions between benzaldehydes and cyclohexanone. Activated charcoal could be recycled five times without the significant decrease of yields.
The synthesis and structural characterization of furanyl-1,2,3-triazole Gold(I) and its application in synthesis of enones from propargylic esters and alcohols
Yao, Wei,Zhang, Yilin,Xu, Xiaqing,Yang, Yongchun,Zeng, Wei,Wang, Dawei
supporting information, (2019/10/04)
Furanyl-1,2,3-triazole gold(I) was designed, synthesized and characterized by X-ray crystallography, and was found to exhibit high catalytic activity for the synthesis of enones in good to high yields through a propargylic ester rearrangement and subsequent hydration. Notably, excellent E/Z selectivity was observed in these transformations. This catalyst was also effective in catalyzing the rearrangement of propargylic alcohols and hydration of alkynes. Compared to triazole acetyl gold(III) and other gold complexes, the furanyl-1,2,3-triazole gold(I) is able to promote these transformations smoothly at a low temperature with the E isomer of enones as the only product.
A Tunable Route to Prepare α,β-Unsaturated Esters and α,β-Unsaturated-γ-Keto Esters through Copper-Catalyzed Coupling of Alkenyl Boronic Acids with Phosphorus Ylides
Bi, Hong-Yan,Liu, Feng-Ping,Liang, Cui,Su, Gui-Fa,Mo, Dong-Liang
supporting information, p. 1510 - 1516 (2018/03/05)
A tunable strategy to prepare α,β-unsaturated esters and α,β-unsaturated-γ-keto esters in good to excellent yields was developed through copper-catalyzed oxidative coupling of phosphorus ylides with alkenyl boronic acids under mild conditions. The reaction without water afforded α,β-unsaturated esters, ketones, and amides while α,β-unsaturated-γ-keto esters, 1,4-α,β-unsaturated diketones and α,β-unsaturated-γ-keto amides were obtained when using 5.0 equiv. of water. H2O18 labeling experiments showed that water played an important role in the formation of α,β-unsaturated-γ-keto esters. A plausible formation mechanism for α,β-unsaturated esters and α,β-unsaturated-γ-keto esters was proposed based on mechanistic studies. Phosphonium salts could also be used directly as coupling partners instead of phosphorus ylides. The reaction exhibited a broad substrate scope, good functional group tolerance, good regioselectivity, and diverse coupling products. (Figure presented.).
Metal- and Acid-Free Methyl Triflate Catalyzed Meyer-Schuster Rearrangement
Yang, Lu,Zeng, Qingle
, p. 3149 - 3156 (2017/07/12)
A novel metal- and acid-free preparation of synthetically useful α,β-unsaturated carbonyl compounds from propargyl alcohols has been realized. This Meyer-Schuster rearrangement process is effectively catalyzed by methyl triflate (20 mol%) to prepare a broad scope of conjugated E -enals and E -enones generally in good to excellent yields (up to 90%). This reaction procedure operates under mild conditions (70 °C), in air, with short reaction times (1 h). Moreover, a carbocation intermediate trapped by the solvent 2,2,2-trifluoroethanol was isolated during this transformation.
Gold- N-Heterocyclic Carbene Complexes of Mineral Acids
Brill, Marcel,Nahra, Fady,Gómez-Herrera, Alberto,Zinser, Caroline,Cordes, David B.,Slawin, Alexandra M. Z.,Nolan, Steven P.
, p. 117 - 120 (2017/01/17)
We have synthesized and characterized new gold-N-heterocyclic carbene (NHC) complexes derived from the deprotonation of mineral acids. The use of sulfuric acid was a particularly interesting case. These complexes were tested in known gold-catalyzed reactions, such as the hydration of alkynes and the Meyer–Schuster rearrangement. They proved to be highly efficient in both reactions.
Vanadium(V)-mediated rearrangement/halogenation cascade: Synthesis of α-haloenones from propargyl alcohols
Zhao, Meng,Mohr, Justin T.
, p. 4115 - 4124 (2017/06/29)
A method is described for the oxidative Meyer–Schuster-type rearrangement of propargylic alcohols to (Z)-α-chloro- and α-iodoenones using VOCl3 as a multifunctional reagent. The vanadium reagent is found to serve as rearrangement promoter as well as an active chlorenium ion donor. Yields are improved when VOCl3 is employed in conjunction with N-halosuccinimide reagents, giving some insights into the complex mechanism.
Anchoring Triazole-Gold(I) Complex into Porous Organic Polymer to Boost the Stability and Reactivity of Gold(I) Catalyst
Cai, Rong,Ye, Xiaohan,Sun, Qi,He, Qiuqin,He, Ying,Ma, Shengqian,Shi, Xiaodong
, p. 1087 - 1092 (2017/08/09)
Stability and reactivity have been recognized as some critical issues for gold(I) catalysts. Such issues can be well-circumvented by anchoring the gold(I) complex onto the backbones of porous organic polymer (POP) followed by coordination with a triazole ligand as illustrated in the present work via a series of gold(I)-catalyzed reactions. In this strategy, 1,2,3-triazole was used as the special "X-factor" to avoid the formation of solid AgCl involved in typical gold-activation processes. The catalyst could be readily recycled without loss of reactivity. Moreover, compared with the PPh3-modified polystyrene beads, the POP support was advantageous by providing high surface area, hierarchical porosity, and better stabilization of cations. In some cases, significantly improved reactivity was observed, even more so than using the homogeneous system, which further highlighted the great potential of this heterogeneous gold catalyst.
Z- and E-selective Horner–Wadsworth–Emmons reactions
Molnár, Katalin,Takács, László,Kádár, Mihály,Faigl, Ferenc,Kardos, Zsuzsanna
, p. 1214 - 1224 (2017/07/06)
In the present work, we determined and evaluated the stereochemical outcome of the Horner–Wadsworth–Emmons (HWE) reaction of 2-oxoalkylphosphonates with different ester functions (bis(2,2,2-trifluoroethyl), 2,2,2-trifluoroethyl methyl, dimethyl) and side chains (aliphatic, aromatic) with three different aldehydes (benzaldehyde, THP- and PPB-protected Corey aldehydes) under two reaction conditions. The “trans” protocol is generally used in the E-selective HWE reactions, while “cis” protocol promotes the Z-selectivity.
Zinc mediated direct transformation of propargyl N-hydroxylamines to α,β-unsaturated ketones and mechanistic insight
Das, Prasanta,Hamme, Ashton T.
, p. 1086 - 1089 (2017/03/02)
A Lewis acid catalyzed direct transformation of propargyl N-hydroxylamines to α,β-unsaturated ketones in the presence of aqueous Zn(II)-salts has been described. This investigation also provides a novel observation for the stoichiometric role of Zn-halides over what is known to date for catalytic processes. A thorough mechanistic study has been established based on the experiment using18O-labeled water in optimized reaction conditions; the incorporation of18O in the desired product was also substantiated by HRMS. This methodology is also a mild, inexpensive, and an efficient approach for this unusual conversion.
Method for preparing alpha and beta-unsaturated ketone
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Paragraph 0012; 0013; 0034; 0035; 0036; 0040; 0041, (2016/10/31)
The invention provides a method for preparing alpha and beta-unsaturated ketone. The method includes that L-proline is used as a catalyst, secondary amine is used as a cocatalyst, and the alpha and beta-unsaturated ketone can be directly synthesized in alcohol or ketone solution by means of aldol condensation under neutral conditions at one step. Compared with the traditional method, the method has the advantages that raw materials are easily available, the method is low in cost and is environmental friendly, reaction conditions are mild, solvents are clean and environmental friendly, equipment can be protected against corrosion under the neutral conditions, the catalyst is high in acid resistance, and the method is applicable to industrial production.
