31892-99-6Relevant academic research and scientific papers
Controlling Enantioselectivity and Diastereoselectivity in Radical Cascade Cyclization for Construction of Bicyclic Structures
Lee, Wan-Chen Cindy,Mckillop, Alexander M.,Wang, Duo-Sheng,Zhang, Congzhe,Zhang, X. Peter
supporting information, p. 11130 - 11140 (2021/07/31)
Radical cascade cyclization reactions are highly attractive synthetic tools for the construction of polycyclic molecules in organic synthesis. While it has been successfully implemented in diastereoselective synthesis of natural products and other complex compounds, radical cascade cyclization faces a major challenge of controlling enantioselectivity. As the first application of metalloradical catalysis (MRC) for controlling enantioselectivity as well as diastereoselectivity in radical cascade cyclization, we herein report the development of a Co(II)-based catalytic system for asymmetric radical bicyclization of 1,6-enynes with diazo compounds. Through the fine-tuning of D2-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under mild conditions, enables asymmetric construction of multisubstituted cyclopropane-fused tetrahydrofurans bearing three contiguous stereogenic centers, including two all-carbon quaternary centers, in high yields with excellent stereoselectivities. Combined computational and experimental studies have shed light on the underlying stepwise radical mechanism for this new Co(II)-based cascade bicyclization that involves the relay of several Co-supported C-centered radical intermediates, including α-, β-, γ-, and ?-metalloalkyl radicals. The resulting enantioenriched cyclopropane-fused tetrahydrofurans that contain a trisubstituted vinyl group at the bridgehead, as showcased in several stereospecific transformations, may serve as useful intermediates for stereoselective organic synthesis. The successful demonstration of this new asymmetric radical process via Co(II)-MRC points out a potentially general approach for controlling enantioselectivity as well as diastereoselectivity in synthetically attractive radical cascade reactions.
New orally active diphenylmethyl-based ester analogues of dihydroartemisinin: Synthesis and antimalarial assessment against multidrug-resistant Plasmodium yoelii nigeriensis in mice
Chaudhary, Sandeep,Naikade, Niraj K.,Tiwari, Mohit K.,Yadav, Lalit,Shyamlal, Bharti Rajesh K.,Puri, Sunil K.
, p. 1536 - 1541 (2016/07/27)
A new series of ester analogues of artemisinin 8a–f, incorporating diphenylmethyl as pharmacologically privileged substructure, and 8g–j have been prepared and evaluated for their antimalarial activity against multidrug-resistant (MDR) Plasmodium yoelii nigeriensis in Swiss mice via oral route. These diphenylmethyl-based ester analogues 8a–f were found to be 2–4 folds more active than the antimalarial drugs β-arteether 4 and artesunic acid 5. Ester 8a, the most active compound of the series, provided complete protection to the infected mice at 24?mg/kg?×?4?days as well as 12?mg/kg?×?4?days, respectively. In this model β-arteether provided 100% and 20% protection at 48?mg/kg?×?4?days and 24?mg/kg?×?4?days, respectively.
Polystyrene resin supported palladium(0) (Pd@PR) nanocomposite catalyzed synthesis of β-aryl and β,β-diaryl unsaturated scaffolds following tandem approaches
Shil, Arun K.,Das, Pralay
, p. 24859 - 24863 (2015/03/30)
A one pot general tandem procedure is described for β-aryl and β,β-diaryl alkenes synthesis following an alternative to the classical approaches by using aryl aldehyde as one of the starting materials. The developed polystyrene resin supported palladium(0) (Pd@PR) nanocomposite has been applied in an unprecedented sequential condensation-decarboxylation-Heck (CDH) and condensation-Heck (CH) strategies to generate the substituted alkenes (C6(C6)CC-C, C6-CC-C6, and C6(C6)CC-CO-C6 units) under ligand, and additive free milder basic reaction conditions. The added momentous benefit over the classical methodologies is in terms of its multi-component approach to achieve the desired products without tedious step wise purifications. This journal is
Synthesis of coumarins via PIDA/I2-mediated oxidative cyclization of substituted phenylacrylic acids
Li, Jinming,Chen, Huiyu,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
, p. 4311 - 4320 (2013/04/24)
A variety of functionalized coumarins were synthesized from substituted phenylacrylic acids via PIDA/I2-mediated and irradiation-promoted oxidative carbon-oxygen bond formation. Our studies show that the oxygen in the pendant carboxylic acid group cyclizes favorably to the aryl ring that is cis to it. The main advantages of this method include good functional group tolerance and the transition-metal-free characteristic. The Royal Society of Chemistry 2013.
Controlled mono- and double-Heck reaction catalyzed by a dicarbene dipalladium complex
Li, Yunfei,Liu, Gang,Cao, Changsheng,Wang, Shuzhan,Li, Yuling,Pang, Guangsheng,Shi, Yanhui
, p. 6241 - 6250 (2013/07/27)
The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the dicarbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the loading of the palladium catalyst, as well as using different base, and with or without additive. The procedure of double-Heck reaction allows β,β- diarylation and β,β′-diarylation of terminal olefins and affords trisubstituted olefins in good to excellent yields.
Synthesis of arylethylene or diarylethylene compounds by Pd-catalyzed heck coupling reaction
Yan, Hong,Sun, Peng,Qu, Xiaoming,Lu, Linhua,Zhu, Yan,Yang, Hailong,Mao, Jincheng
supporting information, p. 2773 - 2783 (2013/08/23)
We have developed an effective palladium-catalyzed arylation or diarylation couplings of olefins with various aryl halides in the presence of readily available ligands. This method is simple, economical, and practical for the synthesis of arylethylene and diarylethylene. Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for full experimental and spectral details.
Solid supported palladium(0) nano/microparticle: A ligand-free efficient recyclable heterogeneous catalyst for mono- and β,β-double-Heck reaction
Sharma, Dharminder,Kumar, Sandeep,Shil, Arun K.,Guha, Nitul Ranjan,Bandna,Das, Pralay
, p. 7044 - 7051 (2013/01/15)
Solid supported palladium nano/microparticles were found to be active catalysts to perform mono- and β,β-double-Heck reactions. Different β-unsubstituted and substituted alkenes including acrylate, methacrylate, crotonate, styrene, acrylonitrile, and acrylamide were investigated successfully for mono- and β,β-double-Heck reactions with aryl iodide under milder reaction condition. One-pot β,β-double-Heck reaction of aryl iodides with α,β-unsaturated ester, amide, nitrile, and styrene derivatives were also performed under standard reaction conditions. Wide functional group tolerance, easy catalyst recovery, and recyclability up to twelve times without significant loss of catalytic activity added extra importance to the present process.
A novel ketone olefination via organozinc reagents in the presence of diphenyl phosphite
Cui, Hua,Li, Ying,Zhang, Songlin
supporting information, p. 2862 - 2869 (2012/11/07)
Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the corresponding olefins. A variety of 1,3-dienes and unsaturated esters were obtained in moderate to excellent yields under mild conditions. The Royal Society of Chemistry 2012.
Palladium-catalyzed double arylations of terminal olefins in acetic acid
Xu, Daichao,Lu, Chunxin,Chen, Wanzhi
experimental part, p. 1466 - 1474 (2012/03/08)
A palladium-catalyzed Heck diarylation of terminal olefins under ligand-free conditions in acetic acid is described. This procedure allows double arylation of terminal olefins affording trisubstituted olefins in good to excellent yields. The methodology is applicable to the coupling of both electron-deficient and electron-rich aryl iodides leading to symmetrical and unsymmetrical β,β-diarylated alkenes.
Palladium-catalyzed intramolecular amidation of C(sp2)-H bonds: Synthesis of 4-aryl-2-quinolinones
Inamoto, Kiyofumi,Saito, Tadataka,Hiroya, Kou,Doi, Takayuki
supporting information; experimental part, p. 3900 - 3903 (2010/07/05)
Figure presented A catalytic synthetic approach for the synthesis of 2-quinolinone compounds through a Pd-catalyzed C(sp2)-H functionalization/intramolecular amidation sequence is described. The cyclization process efficiently proceeds in the p
