33732-62-6Relevant academic research and scientific papers
Probing the Peroxycarbenium [3+2] Cycloaddition Reactions with 1,2-Disubstituted Ethylenes: Results and Insights
Xu, Ze-Jun,Wittlin, Sergio,Wu, Yikang
, p. 2031 - 2034 (2017)
The causes for the title reaction to be limited to only the alkenes with an unsubstituted terminal alkenic carbon were explored. In some “failed” cases the cycloaddition products actually formed but rearranged concurrently. An oxygen atom or a N-Boc (Boc=
Synthesis, Application and Kinetic Studies of Chiral Phosphite-Oxazoline Palladium Complexes as Active and Selective Catalysts in Intermolecular Heck Reactions
Mazloomi, Zahra,Magre, Marc,Del Valle, Efrem,Pericàs, Miquel A.,Pàmies, Oscar,van Leeuwen, Piet W. N. M.,Diéguez, Montserrat
, p. 1650 - 1664 (2018/03/21)
This study identifies new phosphite-oxazoline ligands that have been successfully applied in the palladium-catalyzed intermolecular asymmetric Heck reaction. The design of the new phosphite-oxazoline ligands derives from a previous successful generation of phosphine-oxazoline ligands, by replacing the phosphine group with several π-acceptor biaryl phosphite moieties. With these simple modifications, the new phosphite-based ligands, unlike previous phosphine-oxazoline, not only present a modular design with numerous potential phosphite groups available, but they are also air-stable solids, which can be made in the same number of synthetic steps as the phosphine analogues. The substitution of the phosphine by a biaryl phosphite group extended the range of substrates and triflates sources that can be coupled with regio-, enantioselectivities and activities comparable to the few best ones reported. In addition, the ligands that provided the best selectivities contained an isopropyl oxazoline moiety instead of the tert-butyl group found in the related phosphine-oxazoline ligands, which is made from a much more expensive precursor. In this paper we have also carried out kinetic studies and a Hammett plot analysis to determine the rate determining step of this system in the regime of interest. We suggest a likely explanation for the fast Heck reaction of the phosphite-oxazoline catalysts. (Figure presented.).
Efficient endo Cycloisomerization of Terminal Alkynols Catalyzed by a New Ruthenium Complex with 8-(Diphenylphosphino)quinoline Ligand and Mechanistic Investigation
Cai, Tao,Yang, Yu,Li, Wei-Wei,Qin, Wen-Bing,Wen, Ting-Bin
, p. 1606 - 1618 (2018/01/11)
Several new ruthenium complexes supported by the P,N-donor ligand 8-(diphenylphosphino)quinoline (DPPQ) were synthesized, including [RuCl2(DPPQ)2] (1), [Ru(μ-Cl)(DPPQ)2]2(BPh4)2 (2), and [RuCl(DPPQ)2Py](BF4) (3). Complex 2, with only 1 mol % loading, was found to be catalytically active for the endo cycloisomerization of various terminal alkynols to endo-cyclic enol ethers in moderate to excellent yields. In particular, the 7- and 8-endo heterocyclization can be achieved efficiently to give the seven-membered 3-benzoxepine and eight-membered 3-benzo[d]oxocine derivatives. The stoichiometric reactions of 2 with various alkynol substrates have been carried out to investigate the mechanism, which led to a series of seven-, six-, and five-membered oxacyclocarbene ruthenium complexes including [RuCl(DPPQ)2{=CCH2C6H4CH2CH2O}](BPh4) (12) and [RuCl(DPPQ)2{=CCH2(CH2)nCH2O}](BPh4) (n=3, 12′; n=2, 13; n=1, 14). The quantitative transformation of oxacyclocarbene 12 into catalyst 2 and 3-benzoxepine 5 a as well as the efficient catalytic activity of 12 for the endo-cyclization of 2-(2-ethynylphenyl)ethanol (4 a) demonstrated that 12 is a key intermediate involved in the catalytic cycle. Moreover, comparative studies on the modeling reactions and catalytic activity of the series of oxacyclocarbene complexes indicated that the different catalytic activity of 2 for the endo-cycloisomerization of different types of alkynols can be related to the reactivity of the respective ruthenium oxacyclocarbene intermediates.
Cooperative Metal-Ligand Catalyzed Intramolecular Hydroamination and Hydroalkoxylation of Allenes Using a Stable Iron Catalyst
El-Sepelgy, Osama,Brzozowska, Aleksandra,Sklyaruk, Jan,Jang, Yoon Kyung,Zubar, Viktoriia,Rueping, Magnus
supporting information, p. 696 - 699 (2018/02/09)
A new iron-catalyzed chemoselective intramolecular hydroamination and hydroalkoxylation of the readily available α-allenic amines and alcohols to valuable unsaturated 5-membered heterocycles, 2,3-dihydropyrrole and 2,3-dihydrofuran, is reported. Effective
Efficient Formation of 2,3-Dihydrofurans via Iron-Catalyzed Cycloisomerization of α-Allenols
Gudmundsson, Arnar,Gustafson, Karl P. J.,Mai, Binh Khanh,Yang, Bin,Himo, Fahmi,B?ckvall, Jan-E.
, p. 12 - 16 (2018/01/17)
Herein, we report a highly efficient iron-catalyzed intramolecular nucleophilic cyclization of α-allenols to furnish substituted 2,3-dihydrofurans under mild reaction conditions. A highly diastereoselective variant of the reaction was developed as well, g
Enzyme- and Ruthenium-Catalyzed Enantioselective Transformation of α-Allenic Alcohols into 2,3-Dihydrofurans
Yang, Bin,Zhu, Can,Qiu, Youai,B?ckvall, Jan-E.
supporting information, p. 5568 - 5572 (2016/05/09)
An efficient one-pot method for the enzyme- and ruthenium-catalyzed enantioselective transformation of α-allenic alcohols into 2,3-dihydrofurans has been developed. The method involves an enzymatic kinetic resolution and a subsequent ruthenium-catalyzed c
Asymmetric intermolecular heck reaction of aryl halides
Wu, Chunlin,Zhou, Jianrong
supporting information, p. 650 - 652 (2014/02/14)
The asymmetric intermolecular Heck reaction has been limited to aryl and vinyl triflates. Herein, we extend the reaction to aryl and vinyl bromides. Various cyclic olefins coupled with high enantioselectivity. Only bisphosphine oxides on a spiro backbone formed highly stereoselective Pd catalysts. The use of alcoholic solvents and alkylammonium salts were essential to promote halide dissociation from neutral arylpalladium complexes.
SPIRO-1,1'-BIINDANE-7,7-BISPHOSPHINE OXIDES AS HIGHLY ACTIVE SUPPORTING LIGANDS FOR PALLADIUM-CATALYZED ASYMMETRIC HECK REACTION
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Page/Page column 46, (2015/01/06)
The present invention relates to catalyst complexes comprising palladium (Pd) and at least one spiro-1,1 '-biindane-7,7'- bisphosphine oxide ligand as disclosed herein, and their use. The present invention is further directed to the asymmetric Pd-catalyzed covalent carbon-carbon single bond formation from aryl, heteroaryl and alkenyl triflates and halides and olefins utilising the said catalyst complexes.
Palladium catalyzed heck arylation of 2,3-Dihydrofuran-effect of the palladium precursor
Morel, Adam,Trzeciak, Anna M.,Pernak, Juliusz
, p. 8402 - 8413 (2014/07/08)
Heck arylation of 2,3-dihydrofuran with iodobenzene was carried out in systems consisting of different palladium precursors (Pd2(dba) 3, Pd(acac)2, PdCl2(cod), [PdCl(allyl)] 2, PdCl2(PhCN)
Phosphite-oxazole/imidazole ligands in asymmetric intermolecular Heck reaction
Mazuela, Javier,Tolstoy, Paivi,Pamies, Oscar,Andersson, Pher G.,Dieguez, Montserrat
experimental part, p. 941 - 946 (2011/03/22)
We describe the application of a new class of ligands -the phosphite-oxazole/imidazole (L1-L5a-g) - in asymmetric intermolecular Pd-catalyzed Heck reactions under thermal and microwave conditions. These ligands combine the advantages of the oxazole/imidaz
