479586-34-0Relevant academic research and scientific papers
Fine-Tuning the Bicyclo[3.3.1]nona-2,6-diene Ligands: Second Generation 4,8-Substituted Dienes for Rh-Catalyzed Asymmetric 1,4-Addition Reactions
Bieliūnas, Vidmantas,Ston?ius, Sigitas
, p. 3815 - 3823 (2021/07/28)
Design and synthesis of the second generation C2-symmetric 4,8-endo,endo-bis(alkoxy) bicyclo[3.3.1]nona-2,6-diene ligands possessing additional 4,8-exo,exo substituents is reported. The 4,8-exo,exo groups provide a further element for fine-tuning of the ligand structure by enforcing conformational rigidity of the 4,8-endo,endo side chains. Such tetrasubstituted bicyclo[3.3.1]nona-2,6-dienes were employed as steering ligands in the rhodium-catalyzed arylation of cyclic enones with arylboronic acids, providing the corresponding 1,4-addition products in good to excellent yields (69–99 %) and enantioselectivities up to 99 % ee.
Chiral N-aryl tert-butanesulfinamide-olefin ligands for rhodium-catalyzed asymmetric 1,4-addition of aryl boronic acids to cyclic enones
Yuan, Shuai,Zeng, Qingle,Wang, Jiajun,Zhou, Lihong
supporting information, p. 32 - 42 (2021/02/09)
Chiral N-aryl sulfinamide-olefins which are readily synthesized via C-N coupling and nucleophilic substitution have been used as chiral ligands, which demonstrate moderate to excellent asymmetric catalytic performance in the rhodium-catalyzed asymmetric 1
Organic Solvent-free Asymmetric 1,4-Addition in Liquid- or Solid-State using Conventional Stirring Catalyzed by a Chiral Rhodium Complex Developed as a Homogeneous Catalyst
Korenaga, Toshinobu,Kori, Hiroto,Asai, Shota,Kowata, Ryo,Shirai, Masayuki
, p. 6059 - 6066 (2020/10/28)
Organic solvent-free asymmetric 1,4-addition of arylboronic acids to enone substrates was performed by using a chiral rhodium complex catalyst developed as a homogeneous catalyst. Reactions catalyzed by [RhOH(cod)]2 with chiral diphosphine ligands in liquid- or solid-state proceeded to give chiral 1,4-adducts in high yield with enantioselectivities up to ca. 100 % ee by conventional stirring without mechanochemistry such as ball milling. The solid-state reactions under a static condition also proceeded, but with a slight decrease in enantioselectivity of the 1,4-adduct. SEM observations of the solid-state reactions indicated that no nanoparticles catalyst was generated. The organic solvent-free reaction could be applied to gram-scale synthesis by performing a greener purification using a minimum necessary organic solvent.
Phospholane-Phosphite Ligands for Rh Catalyzed Enantioselective Conjugate Addition: Unusually Reactive Catalysts for Challenging Couplings
Clarke, Matthew L.,Cordes, David B.,Fuentes, José A.,Gilbert, Sophie H.,Slawin, Alexandra M. Z.
supporting information, (2020/05/25)
The use of Rh catalysts derived from a phospholane-phosphite ligand were found to be more productive than the classic rhodium/BINAP system in enantioselective conjugate additions. These catalysts enable the use of lower amounts of aryl boronic acid in an
Tricyclic Sulfoxide-Alkene Hybrid Ligands for Chiral Rh(I) Complexes: The "Matched" Diastereomer Catalyzes Asymmetric C-C Bond Formations
Nikol, Alexander,Zhang, Ziyun,Chelouan, Ahmed,Falivene, Laura,Cavallo, Luigi,Herrera, Alberto,Heinemann, Frank W.,Escalona, Ana,Frie?, Sibylle,Grasruck, Alexander,Dorta, Romano
supporting information, p. 1348 - 1359 (2020/03/30)
Deprotonation of phenyldibenzo[b,f]tropylidene (8) with LDA/t-BuOK followed by quenching with either diastereomer of inexpensive glucose-based t-Bu-sulfinate (R)- or (S)-11 affords a sulfoxide-alkene hybrid ligand as the diastereomeric pairs (SS,SC)-9/(SS,RC)-10 and (RS,RC)-9/(RS,SC)-10, respectively, which via chromatographic/recrystallization may be separated into the four isomers. The optically pure diastereomeric ligands (SS,SC)-9 and (SS,RC)-10 react with [RhCl(coe)2]2 to form the dinuclear complexes (RS,SC)-11 and (RS,RC)-12, respectively, in which the bidentate ligands coordinate the metal centers through the sulfur and alkene donor functions. These complexes catalyze the conjugate addition of arylboronic acids to cyclic Michael acceptors with enantioselectivities of up to 99% ee. DFT calculations show the preponderant influence of planar chirality of the ligand alkene function. The enantioselectivity switch observed between (RS,SC)-11 and (RS,RC)-12 is explained by the inverted cis-trans coordinations of the substrate molecules in catalytic steps.
CHIRAL RHODIUM COMPLEX, AND METHOD FOR PRODUCING β-SUBSTITUTED CARBONYL COMPOUND
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Paragraph 0033-0035, (2021/05/26)
PROBLEM TO BE SOLVED: To provide a chiral complex which, when used as a catalyst, can make an aromatic boronic acid undergo asymmetric 1,4-addition to a conjugated enone in an aqueous solvent under relatively mild conditions and can be recovered by filtration; and a method for producing an optically active β-substituted carbonyl compound using the same as the catalyst. SOLUTION: Provided is a chiral rhodium complex represented by the following formula (α). [In the formula (α), A represents a polystyrene-polyethylene glycol copolymer resin.] SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
Steric Tuning of Sulfinamide/Sulfoxides as Chiral Ligands with C1, Pseudo-meso, and Pseudo-C2 Symmetries: Application in Rhodium(I)-Mediated Arylation
Borrego, Lorenzo G.,Recio, Rocío,álvarez, Eleuterio,Sánchez-Coronilla, Antonio,Khiar, Noureddine,Fernández, Inmaculada
supporting information, p. 6513 - 6518 (2019/08/20)
A new family of sulfinamide/sulfoxide derivatives was synthesized as chiral bidentate ligands by stereoselective additions of methylsulfinyl carbanions to N-tert-butylsulfinylimines. The new ligands, with C1, pseudo-meso, and pseudo-C2 symmetries, were successfully assayed in Rh-catalyzed additions of arylboronic acids to activated ketones. The sterically dissymmetric C1 ligand (RS,SC,RS)-N-[1-(phenylsulfinyl)-3-methylbut-2-yl] tert-butylsulfinamide turned out to be the optimal one, allowing the 1,4-additions of diverse arylboronic acids, on different α,β-unsaturated cyclic ketones with high chemical yields and enantioselectivities up to >99% ee.
Heterogeneous Rh and Rh/Ag bimetallic nanoparticle catalysts immobilized on chiral polymers
Min, Hyemin,Miyamura, Hiroyuki,Yasukawa, Tomohiro,Kobayashi, Shu
, p. 7619 - 7626 (2019/08/20)
The development of heterogeneous chiral catalysts has lagged far behind that of homogeneous chiral catalysts in spite of their advantages, such as environmental friendliness for a sustainable society. We describe herein novel heterogeneous chiral Rh and Rh/Ag bimetallic nanoparticle catalysts consisting of polystyrene-based polymers with chiral diene moieties. The catalysts enable high-to-excellent yields and enantioselectivities to be obtained in asymmetric 1,4-addition reactions of arylboronic acids with α,β-unsaturated carbonyl compounds such as ketones, esters, and amides, and in other asymmetric reactions. The catalysts could be readily recovered by simple filtration and reused; they could also be applied to continuous-flow synthesis. We also discuss the nature of possible reaction species based on XPS analysis.
Heterogeneous Chiral Diene-Rh Complexes for Asymmetric Arylation of α,β-Unsaturated Carbonyl Compounds, Nitroalkenes, and Imines
Kuremoto, Tatsuya,Yasukawa, Tomohiro,Kobayashi, Shū
supporting information, p. 3698 - 3703 (2019/07/12)
A chiral diene ligand with tertiary alkyl amine-derived secondary amide moiety was immobilized on cross-linked polystyrene (PS) by radical polymerization, which was combined with Rh to form heterogeneous chiral Rh complexes (PS-diene Rh?Cl). PS-diene Rh?Cl catalyzed asymmetric arylation reactions of α,β-unsaturated carbonyl compounds (ketones, esters, and amides), nitroalkenes, and imines afforded the desired products in high yields with excellent enantioselectivities. PS-diene Rh?Cl is stable in air, can be stored for several months, and can be reused more than 10 times without any reduction of either yield or enantioselectivity. We also developed a method of activation of PS-diene Rh?Cl to generate more active species. (Figure presented.).
A consecutive process for C-C and C-N bond formation with high enantio-and diastereo-control: Direct reductive amination of chiral ketones using hydrogenation catalysts
Gilbert, Sophie H.,Viseur, Virginie,Clarke, Matthew L.
supporting information, p. 6409 - 6412 (2019/06/07)
High diastereoselectivity was observed in the Rh-catalysed reductive amination of 3-arylcyclohexanones to form tertiary amines. This was incorporated into a one-pot enantioselective conjugate addition and diastereoselective reductive amination, including an example of assisted tandem catalysis.
