86505-50-2Relevant academic research and scientific papers
Enantioselective Hydrogenation of Endocyclic Enones: the Solution to a Historical Problem?
Lang, Qiwei,Yang, Huaxin,Gu, Guoxian,Feng, Qiang,Wen, Jialin,Zhang, Xumu
, p. 933 - 936 (2021/03/03)
The enantioselective hydrogenation of endocyclic enones has been a historical problem for homogeneous catalysis. We herein report an efficient method to reduce endocyclic enones with molecular hydrogen. Catalyzed by a rhodium/Zhaophos complex, a variety of enones with five-, six- or seven-member ring were hydrogenated with high enantioselectivity (92%—99% ee). Excellent chemo- and enantioselectivity demonstrated this method was successfully applied in the enantioselective hydrogenation of citral to produce enantio-enriched citronellal.
Asymmetric Synthesis of Chiral Bicyclo[2.2.1]hepta-2,5-diene Ligands through Rhodium-Catalyzed Asymmetric Arylative Bis-cyclization of a 1,6-Enyne
Chen, Chen,Hayashi, Tamio,Meng, He,Ming, Jialin,Sun, Chao,Wei, Haili
supporting information, p. 6311 - 6315 (2021/09/02)
A series of novel chiral diene ligands (1R,4S)-L1, which are based on the bicyclo[2.2.1]heptadiene skeleton and are substituted with methyl and an ester group at the bridgehead carbons, were synthesized through rhodium-catalyzed asymmetric arylative bis-c
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
Experimental and Theoretical Study on the Role of Monomeric vs Dimeric Rhodium Oxazolidinone Norbornadiene Complexes in Catalytic Asymmetric 1,2- And 1,4-Additions
Abitaev, Karina,Alvarez-Barcia, Sonia,Baro, Angelika,Bauer, Alina,Bauer, Matthias,Estes, Deven P.,Fischer, Felix Richard,Frey, Wolfgang,Gugeler, Katrin,K?stner, Johannes,Kirchhof, Manuel,Laschat, Sabine,Nowakowski, Michal,Plietker, Bernd,Qawasmi, Yaseen,Ringenberg, Mark R.,Schnierle, Marc,Sottmann, Thomas
supporting information, p. 3131 - 3145 (2020/10/02)
The influence of nuclearity and charge of chiral Rh diene complexes on the activity and enantioselectivity in catalytic asymmetric 1,2-additions of organoboron reagents to N-tosylimines and 1,4-additions to enones was investigated. For this purpose, catio
trans-Cyclooctenes as Chiral Ligands in Rhodium-Catalyzed Asymmetric 1,4-Additions
Nagano, Tagui,Einaru, Shunsuke,Shitamichi, Kenta,Asano, Keisuke,Matsubara, Seijiro
supporting information, p. 7131 - 7133 (2020/09/11)
trans-Cyclooctenes serve as asymmetric ligands for the rhodium-catalyzed 1,4-additions of organotin reagents to enones. We demonstrate, for the first time, that these chiral olefins can provide efficient coordination spheres for asymmetric metal catalysis. As the asymmetric environment around the reaction site is constructed by the trans-cyclooctene framework, the introduction of a substituent at the allylic position further improves enantioselectivity to 93 % ee. These findings provide new chiral framework designs for the asymmetric ligands of metal catalysts.
The Silicon-Hydrogen Exchange Reaction: A Catalytic σ-Bond Metathesis Approach to the Enantioselective Synthesis of Enol Silanes
Zhou, Hui,Bae, Han Yong,Leutzsch, Markus,Kennemur, Jennifer L.,Bécart, Diane,List, Benjamin
supporting information, p. 13695 - 13700 (2020/08/24)
The use of chiral enol silanes in fundamental transformations such as Mukaiyama aldol, Michael, and Mannich reactions as well as Saegusa-Ito dehydrogenations has enabled the chemical synthesis of enantiopure natural products and valuable pharmaceuticals. However, accessing these intermediates in high enantiopurity has generally required the use of either stoichiometric chiral precursors or stoichiometric chiral reagents. We now describe a catalytic approach in which strongly acidic and confined imidodiphosphorimidates (IDPi) catalyze highly enantioselective interconversions of ketones and enol silanes. These "silicon-hydrogen exchange reactions"enable access to enantiopure enol silanes via tautomerizing σ-bond metatheses, either in a deprotosilylative desymmetrization of ketones with allyl silanes as the silicon source or in a protodesilylative kinetic resolution of racemic enol silanes with a carboxylic acid as the silyl acceptor.
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.
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.
A novel, C2-symmetric, chiral bis-cyclosulfinamide-olefin tridentate ligand in Rh-catalyzed asymmetric 1,4-additions
Zhang, Li,Tan, Mingchao,Zhou, Lihong,Zeng, Qingle
supporting information, p. 2778 - 2783 (2018/06/11)
A C2-symmetric, chiral bis-cyclosulfinamide-olefin ligand composed of two 1-oxo-2,3-dihydro-1,2-benzisothiazole moieties with rigid skeletons and a conformationally flexible butenylene chain is disclosed for the first time. HRMS and 1/sup
Synthesis of Highly Enantioenriched Propelladienes and their Application as Ligands in Asymmetric Rh-Catalyzed 1,4-Additions
Pecchioli, Tommaso,Christmann, Mathias
supporting information, p. 5256 - 5259 (2018/09/13)
The first synthesis of highly enantioenriched [4.3.3]propelladienes is reported. The novel bridged bicyclo[3.3.0] dienes were applied as steering ligands in the rhodium-catalyzed asymmetric arylation of cyclic enones. The catalytic system showed high catalytic activity, and the 1,4-adducts were obtained in good to excellent yields (46-99%) with enantioselectivities up to 96% ee.
