74810-84-7Relevant academic research and scientific papers
Ir-catalyzed asymmetric allhylie substitutions with (Phosphoramidite)Ir complexes-resting states, synthesis, and characterization of catalytically active (π-Allyl)Ir complexes
Spiess, Stephanie,Raskatov, Jevgenij A.,Gnamm, Christian,Broedner, Kerstin,Helmchen, Guenter
, p. 11087 - 11090 (2009)
A simple method for the synthesis of Ir complexes of cyclo-metallated phosphoramidite ligands was reported. In a dry Schienk flask under argon, a solution of [{Ir(cod)Cl}2] and L2 in absolute THF was stirred for 20 mm and then AgClO4 and isomer
Ir-catalysed asymmetric allylic substitutions with cyclometalated (phosphoramidite)Ir complexes - resting states, catalytically active (π-Allyl)Ir complexes and computational exploration
Raskatov, Jevgenij A.,Spiess, Stephanie,Gnamm, Christian,Broedner, Kerstin,Rominger, Frank,Helmchen, Guenter
, p. 6601 - 6615 (2010)
Mechanistic aspects of allylic substitutions with iridium catalysts derived from phosphoramidites by cyclometalation were investigated. The determination of resting states by 31P NMR spectroscopy led to the conclusion that the cyclometalation process is reversible. A novel, one-pot procedure for the preparation of (πallyl)Ir complexes was developed, and these complexes were characterised by X-ray crystal structure analyses and spectral data. They are fully active catalysts of the allylic substitution reaction. DFT calculations on the allyl complexes, transition states of the allylic substitution and product olefin complexes gave further mechanistic insight.
Allyl 4-Chlorophenyl Sulfone as a Versatile 1,1-Synthon for Sequential α-Alkylation/Cobalt-Catalyzed Allylic Substitution
Kojima, Masahiro,Matsunaga, Shigeki
, p. 1934 - 1946 (2020/07/03)
Despite their unique potential as rare 1,1-dipole synthons, allyl sulfones are rarely used in target-oriented syntheses, likely due to the lack of a general catalytic method for their branch-selective allylic substitution. Herein, we identified allyl 4-chlorophenyl sulfone as a versatile linchpin for both base-mediated α-derivatization and subsequent cobalt-catalyzed allylic substitution. The sequential transformations allow for highly regioselective access to branched allylic substitution products with a variety of aliphatic side chains. The photoredox-enabled cobalt catalysis is indispensable for achieving high yields and regioselectivity for the desulfonylative substitution in contrast to traditional metal-catalyzed protocols, which lead to inferior outcomes in the corresponding transformations.
Water control over the chemoselectivity of a Ti/Ni multimetallic system: Heck- or reductive-type cyclization reactions of alkyl iodides
Millan, Alba,Alvarez De Cienfuegos, Luis,Miguel, Delia,Campana, Araceli G.,Cuerva, Juan M.
supporting information, p. 5984 - 5987 (2013/02/23)
A versatile Ti/Ni multimetallic protocol is described for the efficient catalysis of two different reactions, namely a Heck- and reductive-type cyclization of alkyl iodides, in the absence or presence of water, respectively. Noteworthy, the versatility of
Novel [ruthenium(substituted-tetramethylcyclopentadiene) (2-quinolinecarboxylato)(allyl)] hexafluorophosphate complexes as efficient catalysts for highly regioselective nucleophilic substitution of aliphatic allylic substrates
Zhang, Hui-Jun,Demerseman, Bernard,Toupet, Loic,Xi, Zhenfeng,Bruneau, Christian
supporting information; experimental part, p. 1601 - 1609 (2009/07/18)
Stable [ruthenium(R-substituted-tetramethylcyclopentadiene)(2- quinolinecarboxylato) (1-R′-substituted-allyl) hexafluorophosphate (R = Me, R′ = H, Me, n-Pr, Ph; R = t-Bu, R′ = Me) and [ruthenium(pentamethylcyclopentadiene)(2-quinolinecarboxylato)(1-n-propylallyl)] tetrafluoroborate (4′a), as allylruthenium(IV) complexes, have been synthesized in one step, starting from [ruthenium(R-substituted- tetramethylcyclopentadiene)tris(acetonitrile) hexafluorophosphate or tetrafluoroborate complexes, quinaldic acid, and allylic alcohols. Single stereoisomers are obtained and the X-ray single crystal structure determinations of 3b (R = t-Bu, R′ = Me) and 4′a allow one to specify the preferred arrangement. Complexes 3a (R = R′ = Me) and 3b are involved as precatalysts favoring the formation of branched products in regioselective nucleophilic allylic substitution reactions, starting from ethyl 2-(E)-hexen-1-yl carbonate and chlorohexene as unsymmetrical aliphatic allylic substrates. Phenols, dimethyl malonate, and primary (aniline) and secondary (pyrrolidine, piperidine) amines have been used as nucleophiles under mild basic conditions. For the first time, the regioselectivity in favor of the branched product obtained from purely aliphatic allylic substrates is close to the high regioselectivity previously reached starting from cinnamyl-type substrates in the presence of ruthenium catalysts.
Ruthenium complexes bearing bulky pentasubstituted cyclopentadienyl ligands and evaluation of [Ru(η5-C5Me4R)(MeCN) 3][PF6] precatalysts in nucleophilic allylic substitution reactions
Zhang, Hui-Jun,Demerseman, Bernard,Xi, Zhenfeng,Bruneau, Christian
scheme or table, p. 3212 - 3217 (2009/02/07)
[Ru(η5-C5Me4R)(MeCN) 3][PF6] (R = CH2 tBu, iPr, tBu, and CF 3; 2-5) complexes were synthesized in two steps starting from the appropriate cyclopentadienes and RuCl3·3H2O. The fully substituted ruthenocenes [Ru(C5Me5)(C 5Me4R*)], [Ru(C5Me5)(C 5nPr4R*)] {R* = (1R,5S)-6,6-dimethylbicyclo- [3.1.1]hept-2-en-2-yl} and [Ru(C5Me5)(C 5nPr5)] were obtained by treating [Ru(C5Me 5)Cl]4 with the corresponding cyclopentadienyllithium salts. Complexes 2-5 were evaluated as catalyst precursors for nucleophilic allylic substitution reactions, and the results were compared to those obtained with the [Ru(C5Me5)(MeCN)3][PF6] (1) precatalyst. The etherification of p-methoxyphenol with the typical aliphatic chlorohexene allylic substrate shows that the introduction of the bulky tert-butyl and trifluoromethyl groups into the tetramethylcyclopentadienyl ring results in a valuable enhancement in regioselectivity in favour of the branched allyl aryl ether. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Features and applications of [Rh(CO)2Cl]2-catalyzed alkylations of unsymmetrical allylic substrates
Ashfeld, Brandon L.,Miller, Kenneth A.,Smith, Anna J.,Tran, Kristy,Martin, Stephen F.
, p. 9018 - 9031 (2008/03/13)
(Chemical Equation Presented) A novel regio- and stereoselective [Rh(CO)2Cl]2-catalyzed allylic alkylation of unsymmetrical allylic carbonates was discovered. The regioselectivity of the reaction favors product ratios in which substitution occurs at the carbon bearing the leaving group. When an enantiomerically enriched carbonate (≥99% ee) was examined, the Rh(I)-catalyzed allylic alkylation proceeded stereoselectively to provide the alkylation product with retention of absolute stereochemistry (98% ee). To establish the scope of the [Rh(CO)2Cl]2-catalyzed allylic alkylation, a variety of carbon and heteroatom nucleophiles were examined and the results described. As an application of the Rh(I)-catalyzed allylic alkylation, a series of novel domino reactions have been developed that couple the unique regio- and stereoselective [Rh(CO)2Cl]2- catalyzed alkylation of allylic trifluoroacetates with an intramolecular Pauson-Khand annulation, a cycloisomerization, or a [5+2] cycloaddition. A unique aspect of the method described is the use of a single catalyst to effect sequential transformations in which the catalytic activity is moderated simply by controlling the reaction temperature. Implementation of such processes provides a rapid and efficient entry to a variety of bicyclic carbon skeletons from simple precursors.
TRANSFER OF ASSYMETRY BY THE PALLADIUM-CATALYZED ALKYLATION OF CHIRAL ALLYLIC SULFINATES
Hiroi, Kunio,Kitayama, Ryuichi,Sato, Shuko
, p. 929 - 932 (2007/10/02)
The pallladium-catalyzed substitution of chiral allylic sulfinates was performed by the initial transformation of the sulfinates into allyl sulfones and the subsequent alkylation of the sulfones with retention of configuration.Reaction of trans- and cis-2-butenyl (S)-(-)-p-toluenesulfinate with the sodium salt of dimethyl malonate was undertaken in the presence of tetrakis(triphenylphosphine)palladium and triphenylphosphine to produce dimethyl (S)-(+)- and (R)-(-)-1-buten-3-ylmalonate, respectively, with the α-alkylated product, dimethyl 2-butenylmalonate.
