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21.
This report details an eight‐step synthesis of the thiophene‐type nonlinear optical chromophore 1 in 38% overall yield. Only one early step required chromatography. 相似文献
22.
N‐Ethyl‐3‐styrylindoles are prepared under modified Wittig–Horner reaction conditions. 相似文献
23.
B. Toumi A. Samarat A. Harizi H. Amri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):652-657
Ethyl α-cyanoalkyl β-substituted acrylates 5a–i were prepared in good yields on a synthetic scale by Horner–Wadsworth–Emmons olefination of the corresponding ethyl 2-(diethoxy-phosphoryl) cyanoalkanoates 3a–c using different aldehydes and anhydrous potassium carbonate in dry THF at reflux. 相似文献
24.
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. 相似文献
25.
Oscar Abelardo Ramírez-Marroquín Flavio Manzano-Pérez Adolfo López-Torres Alejandro Hernández-López Abimelek Cortés-Pacheco Miguel Angel Reyes-González 《合成通讯》2019,49(2):244-255
Piperlotines are natural products characterized by an α,β-unsaturated amide moiety. These compounds found wide applications in Medicinal Chemistry like antibacterials, cytotoxic agents, anticoagulants, among others. To date, diverse methods of synthesis have been reported for piperlotines, but involving the use of catalysts, hazard reagents, anhydrous media or coupling reagents. Thus, in this work, we developed a greener method of synthesis of piperlotines A, C, and derivatives, through mechanochemical activation under solvent-free conditions. The reaction of a β-amidophosphonate, K2CO3, and an aromatic aldehyde afforded target compounds in moderate to good yields (46–77%), in an open atmosphere by grinding. It is worth to mention that this mechanochemical process was under thermodynamic control because just E isomer was isolated for every reaction. Moreover, synthesized piperlotines have been predicted by means of chemoinformatic analysis as potential therapeutic agents for the treatment of arthritis or cancer. 相似文献
26.
The Horner–Wadsworth–Emmons reaction of ferrocenecarboxaldehyde with various phosphonate-stabilized carbanions has been performed under ultrasound irradiation. The reaction time at ambient temperature was considerably shortened (5–15 min) compared to nonsonicated conditions requiring often refluxing for 6–24 h. Control of the reaction time can be achieved by tuning the base strength in different solvents. This method was successfully applied to the preparation of various 2-substituted vinylferrocenes. The as-prepared (E)-2-ferrocenylvinylphosphonic acid was used to modify ITO electrodes to form redox-active functionalized ITO electrodes which have been characterized by means of electrochemical techniques. 相似文献
27.
Amanda M. Heapy 《Tetrahedron》2010,66(29):5424-5431
The synthesis of the FG ring fragment common to pectenotoxins 1-9 is reported. The successful, convergent synthesis relied on high yielding routes to access two key intermediates; aldehyde 1 and phosphonium salt 2. A Z-selective Wittig reaction gave access to advanced linear precursor 3, which was converted to FG ring fragment 4 using two sequential cyclization reactions. 相似文献
28.
Some chiral oxazaborolidinones were prepared from L-α-amino acids reacting with borane and used as a new type of catalysts for asymmetric reduction of acetophenone with borane to afford R-(+)-1-phenyl ethanol with 23–76%ee in high yield. 相似文献
29.
A task-specific imidazolium-based phosphinite ionic liquid (IL-OPPh2) was used as the dual solvent–reagent for the synthesis of E-cinamates and coumarin derivatives via the one-pot Horner–Wadsworth–Emmons–type reaction. The ionic liquid containing its corresponding phosphinite moiety was reacted with α-chloro esters and benzaldehyde or salicylaldehyde derivatives in the presence of sodium methoxide under microwave irradiation to produce the related E-cinamates or coumarins, respectively. The satisfactory results were obtained with good yields, short reaction time, and simple experimental procedure. 相似文献
30.
The synthesis of potassium aeshynomate and its non-natural stereomers was achieved using the Sharpless catalytic asymmetric dihydroxylation of (Z) or (E) vinylogous glycine as the key step. The resulting γ-amino α,β-dihydroxyester stereomer was deprotected and coupled with the caffeic acid to afford stereoselectively potassium aeshynomate or its stereomers. A detailed study of the NMR data of the different stereomers is reported that corrects the literature data. 相似文献