Asymmetric Hydrogenation of Unfunctionalized Enamines Catalyzed by Iridium Complexes of Chiral Spiro <i>N</i>,<i>N</i>‐Diarylphosphoramidites

Yan, Pu‐Cha; Xie, Jian‐Hua; Zhou, Qi‐Lin

doi:10.1002/cjoc.201090293

Cited by 24 publications

(14 citation statements)

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“…The yield of the alcohol 3 aa was determined after desilylation. To this end, we devised a method for TMS‐deprotection that allowed the whole process to be performed as a one‐pot transformation, simply by treatment of the reaction mixture with silica‐supported sulfuric acid (H 2 SO 4 ⋅SiO 2 ) 16. For aliphatic aldehydes as substrates, some silyl enol ether is typically formed as side product.…”

Section: Methodsmentioning

confidence: 99%

“…To this end, we devised am ethod for TMS-deprotection that allowed the whole process to be performed as ao ne-pot transformation, simply by treatment of the reaction mixture with silica-supported sulfuric acid (H 2 SO 4 ·SiO 2 ). [16] For aliphatic aldehydes as substrates, some silyl enol ether is typically formed as side product. Our desilylation protocol also converts this silyl enol ether back to the corresponding aldehyde.…”

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confidence: 99%

“…The reactivity of 1-iodocyclopentene (2e)a nd of the 1-iodohexenes (E)-2f and (Z)- www.chemeurj.org 2g in the coupling with 1a was found to be lower than that of 2a and 2c.A fter 24 h, the coupling products 3ae-ag were obtained in moderate yield only ( Table 2, entries 14-16), with some 1a and 2 remaining. Extension of the reaction times improvedt he product yields only slightly.N otably,n oZ / Eisomerization was detected in the reactions of 2fand 2g ( Table 2, entries 15,16). Upon increasing NiCl 2 to 0.5 mol %( L1 1.5 mol %), however,p artial Z!E isomerization was observed with 2g, [23] yieldinga11:1 Z/E product mixture in 38 %y ield at 74 %c onversion after 18 h.…”

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Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst

Harnying

Berkessel

2015

Chemistry A European J

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We report an efficient and practical protocol for the Cr/Ni-catalyzed vinylation of aldehydes, based on the use of Mn/Cr alloy (ca. 10 % Cr) and TMSCl. No additional Cr salts need to be added. In the presence of NiCl2 (0.3 mol %) and a bis(ketimino)-2,2'-bipyridine as N4 -chelating ligand (1 mol %), the vinylations proceed smoothly at room temperature. The presence of catalytic amounts of MeOH and LiOAc as additives was found to further promote the efficiency of the catalytic system, even in the absence of the ligand. Detailed reaction monitoring revealed that LiOAc accelerates the product alcohol silylation, thus increasing the turnover rate.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst

Harnying

Berkessel

2015

Chemistry A European J

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“…The polymerization media covers not only the traditional acidic and neutral aqueous solution systems118–121 or a hydrogel system122 but also the alkaline aqueous solution systems 120,123–125…”

Section: Syntheses and Morphology Controlling Of 1d Nano‐panimentioning

confidence: 99%

One‐Dimensional Nanostructured Polyaniline: Syntheses, Morphology Controlling, Formation Mechanisms, New Features, and Applications

Wang¹,

Zhang²

2012

Adv Polym Technol

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One‐dimensional nanostructured polyaniline (1D nano‐PANI), including nanofibers, nanowires, nanobelts, nanotubes, nanorods, nanoneedles, and nanosticks, has been extensively studied recently due to its unique properties and many potential applications. As a continuation of our previous review on 1D nano‐PANI (D. H. Zhang and Y. Y. Wang, Mater Sci Eng B 2006, 134(1), 9–19), the research and development of 1D nano‐PANI, including both syntheses and applications, in the past 5 years (2006–2010) are reviewed in this paper. Newly invented chemical methods for fabrication of 1D nano‐PANI, such as solid‐state polymerization, seeding polymerization, UV light‐ and microwave‐assisted polymerization, plasma‐induced polymerization, porous membrane controlled polymerization, and vapor phase polymerization, are briefly reviewed, and morphology controlling of the nanostructures during several synthesizing processes are reported and discussed at first. The formation mechanisms and key factors that affect the morphology evolution of the 1D nano‐PANI are discussed. Novel features of 1D nano‐PANI, such as aligned or oriented, longer, self‐doped, chiral, derivative, carbonized, and dendritic PANI, are summarized. Finally, newly exploited applications of 1D nano‐PANI in the past few years, such as sensors (e.g., gases sensors, biosensors, moisture or humidity sensors, TNT sensors, taste sensors, and noble metal ion sensors), absorbents, catalysts, actuators, supercapacitors, batteries, fuel cells, solar cells, electrochromic devices, hydrogen storages, surface modifiers, field‐effect transistors, and functional materials, are discussed in detail. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E323–E368, 2013; View this article online at http://wileyonlinelibrary.com. DOI 10.1002/adv.21283

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“…此外, 他们在研究简单非保护烯胺的不对称催化氢化时还发现氮原子上含有两个苯基的手性螺环亚磷酰胺酯配体 Ph-SIPHOS (34)给出了高达 90% ee 的对映选择性. 这表明手性螺环单齿磷配体中, 磷原子上的取代基对烯胺氢化具有显著影响 [48] . [51] (图 20).…”

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New Progress and Prospects of Transition Metal-Catalyzed Asymmetric Hydrogenation

Xie¹,

Zhou²

2012

Acta Chim. Sinica

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165

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Chiral transition metal complexes-catalyzed asymmetric hydrogenation is one of the most efficient methods for the synthesis of optically active compounds, and has been intensively investigated in the past decades. This review presents a brief overview on the progress in the transition metal-catalyzed asymmetric hydrogenation since the beginning of this new century from three aspects: (1) chiral ligands and catalysts; (2) new catalytic asymmetric hydrogenations; (3) new methods and new strategies in asymmetric hydrogenations. Chiral monodentate phosphorus ligands have been a renaissance from the beginning of new century, and many efficient chiral monophosphoramidites such as MonoPhos, SiPhos, DpenPhos have been developed. The chiral phosphine ligands with a chirality on the phosphorus atom (P-chirality), such as BenzP*, ZhanPhos, and TriFer, have also been explored. Chiral ligands with a spiro skeleton have been a highlight of design and synthesis of chiral ligands. The chiral spiro ligands such as SDP, SiPhos, SIPHOX, and SpinPHOX are very efficient in asymmetric hydrogenations. The iridium complexes of chiral spiro pyridine-aminophosphine ligands SpiroPAP is the most efficient molecular catalysts up to now with a turnover number (ratio of converted substrate to catalyst) over 4500000 in the hydrogenation of acetophenone. A number of breakthroughs have been made in the researches on new catalytic asymmetric hydrogenations. Highly enantioslective hydrogenations of unprotected enamines, heteroaromatic compounds, and N-H imines have been developed. New methods and strategies including self-assembled, dendrimerized, and ferromagnetic nanomaterials-loaded chiral catalysts with recyclability and reusability, the catalysts with "mixed" chiral ligands have also been successfully applied in the catalytic asymmetric hydrogenations. However, the chiral transition metal complexes catalyzed asymmetric hydrogenation still has many challenges and is looking forward to new breakthroughs in the future. In addition to the continuous developments of new chiral ligands and catalysts with high efficiency, high enantioselectivity, and high chemoselectivity, new strategies such as co-operative or relay catalysis are becoming focuses of the asymmetric hydrogenations studies.

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Asymmetric Hydrogenation of Unfunctionalized Enamines Catalyzed by Iridium Complexes of Chiral Spiro N,N‐Diarylphosphoramidites

Cited by 24 publications

References 11 publications

Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst

Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst

One‐Dimensional Nanostructured Polyaniline: Syntheses, Morphology Controlling, Formation Mechanisms, New Features, and Applications

New Progress and Prospects of Transition Metal-Catalyzed Asymmetric Hydrogenation

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Asymmetric Hydrogenation of Unfunctionalized Enamines Catalyzed by Iridium Complexes of Chiral Spiro N,N‐Diarylphosphoramidites

Cited by 24 publications

References 11 publications

Vinylation of Aldehydes Using Mn/Cr Alloy and a N4‐Ligand/NiII‐Catalyst

Vinylation of Aldehydes Using Mn/Cr Alloy and a N4‐Ligand/NiII‐Catalyst

One‐Dimensional Nanostructured Polyaniline: Syntheses, Morphology Controlling, Formation Mechanisms, New Features, and Applications

New Progress and Prospects of Transition Metal-Catalyzed Asymmetric Hydrogenation

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Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst

Vinylation of Aldehydes Using Mn/Cr Alloy and a N₄‐Ligand/Ni^II‐Catalyst