- Cage-shaped borate esters with enhanced Lewis acidity and catalytic activity
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A cage shape causes high Lewis acidity and catalytic activity on boron. Borate esters that have cage-shaped ligands have accessible LUMO with lower eigenvalues than normal open-shaped borate esters. A large dihedral angle at C-O-B-O in cage-shaped borate
- Yasuda, Makoto,Yoshioka, Sachiko,Yamasaki, Satoshi,Somyo, Toshio,Chiba, Kouji,Baba, Akio
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Read Online
- Tuning Lewis Acidity by a Transannular pπ–σ* Interaction between Boron and Silicon/Germanium Atoms Supported by a Cage-Shaped Framework
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Cage-shaped borates tethered by heavier Group 14 elements (Si or Ge) were synthesized. These possess an intramolecularly transannular pπ–σ* interaction between the boron center and the tethered Si/Ge atom, which allows the precise tuning of their Lewis acidity. The Lewis acidity was investigated by the ligand-exchange reaction rate and IR measurements with the help of theoretical calculation. The synthesized borates exhibited catalytic activity. This study demonstrated the effectiveness of the direct orbital perturbation of a metal center by space interaction during fine tuning of the Lewis acidity.
- Konishi, Akihito,Nakaoka, Koichi,Nakajima, Hideto,Chiba, Kouji,Baba, Akio,Yasuda, Makoto
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Read Online
- Use of Organometallic Complexes of Ruthenium in the Lewis Acid Catalyzed Hetero Diels-Alder Reaction
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The hetero Diels-Alder reaction between benzaldehyde and a functionalized diene can be catalyzed by the Lewis acid transition metal complexes, PF6 (L=L'=PPh3, or LL'=1,2-bis-diphenylphosphinoethane, (-)-DIOP or (S,S)-CHIRAPHOS).
- Faller, J. W.,Smart, C. J.
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Read Online
- Indium triflate-an efficient catalyst for hetero Diels-Alder reactions
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At a loading as low as 0.5 mol% indium triflate has been found to catalyse the hetero Diels-Alder reaction. A three component coupling reaction between aldehydes, amines and Danishefsky's diene to afford tetrahydropyridine derivatives proceeds similarly i
- Ali, Tayyeb,Chauhan, Kamlesh K.,Frost, Christopher G.
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Read Online
- Synthesis and characterization of sterically crowded aryloxides: ‘Mitsubishi’-class of tetrametallic aluminum complexes
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A new series of tetrameric aluminum molecules with a Mitsubishi structure, composed of two cage-shaped triphenolic ligands with a tripod-chelated structure, have been synthesized and characterized. Transmetalation from the cage-shaped borates was a proper
- Konishi, Akihito,Nakajima, Hideto,Maruyama, Hikaru,Yoshioka, Sachiko,Baba, Akio,Yasuda, Makoto
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Read Online
- Thiazolinium salt: an efficient catalyst for the Mukaiyama reaction
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Mukaiyama aldol reaction between benzaldehyde and Danishefsky diene is promoted by ionic liquid-type salts. Hence, thiazolinium salts have been found to be the most efficient for this transformation. On a mechanistic point of view, only the Mukaiyama proc
- Mercey, Guillaume,Brégeon, Delphine,Baudequin, Christine,Guillen, Frédéric,Levillain, Jocelyne,Gulea, Mihaela,Plaquevent, Jean-Christophe,Gaumont, Annie-Claude
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Read Online
- Chiral Chromium Salen@rGO as Multipurpose and Recyclable Heterogeneous Catalyst
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The first immobilization of a pyrene-tagged chromium salen complex through π-π noncovalent interactions on reduced graphene oxide (rGO) is described. A very robust supported catalytic system is obtained to promote asymmetric catalysis in repeated cycles, without loss of activity or enantioselectivity. This specific behavior was demonstrated in two different catalytic reactions (up to ten reuses) promoted by chromium salen complexes, the cyclohexene oxide ring-opening reaction and the hetero-Diels-Alder cycloaddition between various aldehydes and Danishefsky's diene. Furthermore, the chiral chromium salen@rGO has been found to be compatible with a multi-substrate type use, in which the structure of the substrate involved is modified each time the catalyst is reused.
- Abd El Sater, Mariam,Mellah, Mohamed,Dragoe, Diana,Kolodziej, Emilie,Jaber, Nada,Schulz, Emmanuelle
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supporting information
p. 9454 - 9460
(2021/05/26)
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- Selective Activation of Aromatic Aldehydes Promoted by Dispersion Interactions: Steric and Electronic Factors of a π-Pocket within Cage-Shaped Borates for Molecular Recognition
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Selective bond formations are one of the most important reactions in organic synthesis. In the Lewis acid mediated electrophile reactions of carbonyls, the selective formation of a carbonyl–acid complex plays a critical role in determining selectivity, wh
- Tanaka, Daiki,Tsutsui, Yuya,Konishi, Akihito,Nakaoka, Koichi,Nakajima, Hideto,Baba, Akio,Chiba, Kouji,Yasuda, Makoto
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supporting information
p. 15023 - 15034
(2020/10/20)
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- Catalytic asymmetric oxo-Diels-Alder reactions with chiral atropisomeric biphenyl diols
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New chiral atropisomeric biphenyl diols 3, 4 and 6 containing additional peripheral chiral centers with different steric bulkiness and/or electronic properties were synthesized. The X-ray crystal structure of 3 shows the formation of a supramolecular stru
- Yeung, Chi-Tung,Chan, Wesley Ting Kwok,Lo, Wai-Sum,Law, Ga-Lai,Wong, Wing-Tak
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supporting information
p. 955 - 962
(2019/06/08)
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- Synthesis and Characterization of Pheox– and Phebox–Aluminum Complexes: Application as Tunable Lewis Acid Catalysts in Organic Reactions
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Pheox– and Phebox–aluminum complexes were synthesized and subsequently characterized by spectroscopic analysis. These complexes acted as Lewis acid catalysts, and their catalytic activities were controlled by using the Pheox, Phebox, and heteroatom ligands. The Pheox–aluminum complex exhibited an opposite substrate selectivity to AlCl3 in a competitive hetero-Diels–Alder reaction between electron-rich and electron-deficient aldehydes.
- Nishimoto, Yoshihiro,Nakao, Shuichi,Machinaka, Shota,Hidaka, Fumiko,Yasuda, Makoto
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supporting information
p. 10792 - 10796
(2019/07/05)
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- Synthesis of Cage-Shaped Aluminum Aryloxides: Efficient Lewis Acid Catalyst for Stereoselective Glycosylation Driven by Flexible Shift of Four- To Five-Coordination
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Monomeric cage-shaped aluminum aryl oxides 1Al were synthesized using tripodal triphenolic ligands. The Lewis acidity and catalytic activity of the obtained 1Al·py were investigated. The Lewis acidity of 1Al·py originates from the flexible change in the c
- Tanaka, Daiki,Kadonaga, Yuichiro,Manabe, Yoshiyuki,Fukase, Koichi,Sasaya, Shota,Maruyama, Hikaru,Nishimura, Sota,Yanagihara, Mayu,Konishi, Akihito,Yasuda, Makoto
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supporting information
p. 17466 - 17471
(2019/10/14)
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- Enantiopure (P)- and (M)-3,14-bis(o-hydroxyaryl)tetrahydrobenzo[5]helicenediols and their helicene analogues: Synthesis, amplified circularly polarized luminescence and catalytic activity in asymmetric hetero-Diels–Alder reactions
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Three pairs of enantiopure (P)- and (M)-3,14-bis(o-hydroxyaryl)tetrahydrobenzo[5]helicenediols (ArOH-H[5]HOLs), and enantiomers (P)- and (M)-3,14-bis(o-hydroxyphenyl)benzo[5]helicene-diols (PhOH-[5]HOLs) were designed and synthesized. It was found that co
- Fang, Lei,Li, Meng,Lin, Wei-Bin,Chen, Chuan-Feng
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p. 7164 - 7172
(2018/11/23)
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- C3-Symmetric Boron Lewis Acid with a Cage-Shape for Chiral Molecular Recognition and Asymmetric Catalysis
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Chiral Lewis acids play an important role in the precise construction of various types of chiral molecules. Here, a cage-shaped borate 2 was designed and synthesized as a chiral Lewis acid that possesses a unique C3-symmetric structure composed of three homochiral binaphthyl moieties. The highly symmetrical structure of 2 with homochirality was clearly elucidated by X-ray crystallographic analysis. The peculiar chiral environment of 2?THF exhibited chiral recognition of some simple amines and a sulfoxide. Moreover, the application of 2?THF to hetero-Diels–Alder reactions as a chiral Lewis-acid catalyst afforded the enantioselective products, which were obtained through an entropy-controlled pathway according to the analysis of the relationship between optical yield and reaction temperature. In particular, the robust chiral reaction field of 2?THF allowed the first example of an asymmetric hetero-Diels–Alder reaction with a simple diene despite the requirement of high temperature.
- Konishi, Akihito,Nakaoka, Koichi,Maruyama, Hikaru,Nakajima, Hideto,Eguchi, Tomohiro,Baba, Akio,Yasuda, Makoto
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supporting information
p. 1273 - 1277
(2017/02/05)
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- A Cr(salen)-based metal-organic framework as a versatile catalyst for efficient asymmetric transformations
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A porous Cr(salen)-MOF can serve as an efficient and effective heterogeneous catalyst for a series of important asymmetric transformations including the Nazarov cyclization, aminolysis reaction, and Diels-Alder and hetero Diels-Alder reactions, resulting
- Xia, Qingchun,Liu, Yan,Li, Zijian,Gong, Wei,Cui, Yong
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supporting information
p. 13167 - 13170
(2016/11/09)
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- A Family of Chiral Ferrocenyl Diols: Modular Synthesis, Solid-State Characterization, and Application in Asymmetric Organocatalysis
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Readily available chiral diol scaffolds are useful as sources of chirality for asymmetric synthesis, however, few such scaffolds are readily available in enantiopure form. Reported herein is a cheap and modular synthesis of a novel family of chiral ferroc
- Nottingham, Chris,Müller-Bunz, Helge,Guiry, Patrick J.
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supporting information
p. 11115 - 11119
(2016/10/13)
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- Trans-selective rhodium catalysed conjugate addition of organoboron reagents to dihydropyranones
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The selective synthesis of 2,6-trans-tetrahydropyran derivatives employing the rhodium catalysed addition of organoboron reagents to dihydropyranone templates, derived from a zinc-catalysed hetero-Diels-Alder reaction, is reported. The addition of both arylboronic acids and potassium alkenyltrifluoroborates have been accomplished in high yields using commercially-available [Rh(cod)(OH)]2 catalyst. The selective formation of the 2,6-trans-tetrahydropyran stereoisomer is consistent with a mechanism involving alkene association and carbometalation on the less hindered face of the dihydropyranone.
- Edwards, Hannah J.,Goggins, Sean,Frost, Christopher G.
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p. 6153 - 6166
(2015/05/13)
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- Silica-based helical rod supporting guanosine compounds catalyzed asymmetric hetero-Diels-Alder reaction
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A series of silica-based helical rods were prepared and functionalized for immobilization of guanosine compounds in catalytic asymmetric hetero-Diels-Alder reaction. Nitrogen physisorption, electron microscopy and amino acid adsorption revealed that helic
- Li, Le,Zhang, Guangbin,Huang, Benhua,Ren, Lin,Zheng, Aqun,Zhang, Junjie,Sun, Yang
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- Highly asymmetric hetero-Diels-Alder reaction using helical silica-supported Mn(III)-salen catalysts
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Helical silica were prepared and functionalized by Mn(III)-salen complexes in order to catalyze asymmetric hetero-Diels-Alder reactions. Characterizations revealed doping of sodium lactate facilitated porosity, hydrolysis resistance and chiral configurati
- Li, Le,Li, Yu,Pang, Di,Liu, Fei,Zheng, Aqun,Zhang, Guangbin,Sun, Yang
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p. 8096 - 8103
(2015/12/30)
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- Comparison of a molecular and an immobilized gadolinium(III)-tris[(1R,4S)- 3-heptafluorobutanoyl-camphor] as catalyst in the asymmetric Danishefsky-hetero-Diels-Alder-Reaction
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On-column reaction gas chromatography combines the power of separation and rapid analysis of reactants and reaction products with screening of reactions in a single step. Not only conversions but the reaction rates at various temperatures can be obtained
- Stockinger, Skrollan,Trapp, Oliver
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p. 243 - 248
(2014/04/17)
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- Planar-chiral bis-silanols and diols as h-bonding asymmetric organocatalysts
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The successful development of planar-chiral bis-silanols 3a-d and their application as asymmetric organocatalysts in hetero-Diels-Alder (HDA) reactions is described. All precursors were easily prepared by addition of commerically available silyl electrophiles to a dilithiated [2.2]paracyclophane derivative followed by silane oxidations. The analogous bis-carbinols 7a-c have been prepared by addition of suitable Grignard reagents to bis-methoxycarbonyl derivative 6. Both racemic as well as enantiopure planar-chiral bis-silanols and bis-carbinols were obtained in good yields. The catalytic activities of the bis-silanols were analyzed by monitoring HDA reactions between Rawal's diene and aldehydes by in situ IR spectroscopy and comparing the resulting data with those obtained in catalyses with the corresponding bis-carbinol derivatives. The results show for the first time that planar-chiral bis-silanols with hydrogen-bonding capabilities can be applied as asymmetric organocatalysts leading to enantiomerically enriched products. Enantiopure, planar-chiral [2.2]paracyclophane-based bis-silanols and their carbon diol analogs were synthesized and used as hydrogen-bond-donating organocatalysts in a hetero-Diels-Alder reaction with Rawal's diene.
- Beemelmanns, Christine,Husmann, Ralph,Whelligan, Daniel K.,Oezcubukcu, Salih,Bolm, Carsten
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supporting information; experimental part
p. 3373 - 3376
(2012/08/07)
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- Synthesis and application of azolium ionic liquid tagged TADDOL catalysts
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Ionic liquid (IL) tagged organocatalysts based on TADDOL (α, α, α′, α′-tetraaryl-2,2-dimethyl-1,3-dioxolane-4,5- dimethanol) comprising various aryl substituents tethered with triazolium and imidazolium based ionic liquids are synthesised in good yields.
- Yacob, Zekarias,Liebscher, Juergen
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p. 312 - 319
(2013/09/24)
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- Recognition of aromatic compounds by π pocket within a cage-shaped borate catalyst
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Taking shape: The ability of a Lewis acid catalyst to distinguish between aromatic and aliphatic hydrocarbon moieties was accomplished by using cage-shaped borate catalysts B(OC6H3Aryl)3CH (see picture) having a π pocket derived from aryl substituents surrounding the boron center. The catalyst predominantly activated aromatic aldehydes over aliphatic ones for reaction. Copyright
- Nakajima, Hideto,Yasuda, Makoto,Takeda, Ryosuke,Baba, Akio
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supporting information; experimental part
p. 3867 - 3870
(2012/06/15)
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- cis-2,5-diaminobicyclo[2.2.2]octane, a new scaffold for asymmetric catalysis via salen-metal complexes
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Chemical equations presented. A new C2 symmetric salen scaffold based on cis-2,5-diaminobicyclo[2.2.2]octane has been synthesized that forms complexes with a wide range of metals. The chromium(III) complex is shown to catalyze the hetero-Diels-
- White, James D.,Shaw, Subrata
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supporting information; experimental part
p. 2488 - 2491
(2011/06/25)
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- Cage-shaped borate esters with tris(2-oxyphenyl)methane or -silane System frameworks bearing multiple tuning factors: Geometric and substituent effects on their lewis acid properties
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Boron complexes that contain new tridentate ligands, tris(o-oxyaryl) methanes and -silanes, were prepared. These complexes had a cage-shaped structure around a boron center and showed higher Lewis acidity and catalytic activity than open-shaped boron compounds. The cage-shaped ligands determined the properties of the borates by altering the geometry and were consistently bound to the metal center by chelation. The synthesized compounds were L·B(OC6H4)3CH, L·B(OC 6H4)3SiMe, and its derivatives (L=THF or pyridine as an external ligand). Theoretical calculations suggested that the cage-shaped borates had a large dihedral angle (Cipso-O-B-O) compared with open-shaped borates. The geometric effect due to the dihedral angle means that compared with open-shaped, the cage-shaped borates have a greater Lewis acidity. The introduction of electron-withdrawing groups on the aryl moieties in the cage-shaped framework increased the Lewis acidity. Substitution of a bridgehead Si for a bridgehead C decreased the Lewis acidity of the boron complexes because the large silicon atom reduces the dihedral angle of C ipso-O-B-O. The ligand-exchange rates of the para-fluoro-substituted compound B(OC6H3F)3CH and the ortho-phenyl-substituted compound B(OC6H3Ph)3CH were less than that of the unsubstituted borate B(OC6H 4)3CH. The ligand-exchange rate of B(OC6H 4)3SiMe was much faster than that of B(OC 6H4)3CH. A hetero Diels-Alder reaction and Mukaiyama-type aldol reactions were more effectively catalyzed by cage-shaped borates than by the open-shaped borate B(OPh)3 or by the strong Lewis acid BF3·OEt2. The cage-shaped borates with the bulky substituents at the ortho-positions selectively catalyzed the reaction with less sterically hindered substrates, while the unsubstituted borate showed no selectivity.
- Yasuda, Makoto,Nakajima, Hideto,Takeda, Ryosuke,Yoshioka, Sachiko,Yamasaki, Satoshi,Chiba, Kouji,Baba, Akio
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supporting information; experimental part
p. 3856 - 3867
(2011/05/16)
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- CHIRAL DISULFONIMIDES
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Chiral disulfonimides having the formula I to III, wherein at least one of the groups A and B in the compound of formula I, C and D of the compound in formula II, and E and F of the compound in formula III is a chiral group, or E and F together form a chi
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Page/Page column 19
(2012/01/13)
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- Control of selectivity in the generation and reactions of oxonium ylides
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Dirhodium catalyzed reactions of aryl-substituted tetrahydropyranone diazoacetoacetates produce ylide intermediates that unexpectedly yield two oxabicyclo[4.2.1]-nonane diastereoisomers, but a single diastereoisomer is formed by increasing the steric bulk of the aryl substituent.
- Jaber, Deana M.,Burgin, Ryan N.,Hepler, Matthew,Zavalij, Peter,Doyle, Michael P.
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supporting information; experimental part
p. 7623 - 7625
(2011/09/12)
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- Evaluation of catalyst acidity and substrate electronic effects in a hydrogen bond-catalyzed enantioselective reaction
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A modular catalyst structure was applied to evaluate the effects of catalyst acidity in a hydrogen bond-catalyzed hetero Diels-Alder reaction. Linear free energy relationships between catalyst acidity and both rate and enantioselectivity were observed, wh
- Jensen, Katrina H.,Sigman, Matthew S.
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experimental part
p. 7194 - 7201
(2011/01/12)
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- Oxo-Diels-Alder reaction of danishefskys diene with aldehydes, catalyzed by chiral tridentate chromium(III)-Schiff base complexes
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The enantioselective hetero-Diels-Alder reaction of Danishefskys diene with simple aromatic and aliphatic aldehydes is catalyzed by chiral tridentate Schiff base-chromium(III) complexes. In many cases, 2,3-dihydropyran-4-ones are obtained in good yields (
- Miesowicz, Sawomir,Chaladaj, Wojciech,Jurczak, Janusz
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scheme or table
p. 1421 - 1425
(2010/08/06)
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- Synthesis and theoretical studies of gallium complexes back-shielded by a cage-shaped framework of tris(m-oxybenzyl)arene
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Cage-shaped gallium complexes with a back-shielding framework of tris(m-oxybenzyl)arene were synthesized, their bottom arene rings tuned their characteristic Lewis acidity, which was supported by theoretical calculation as well as catalytic application in a hetero Diels-Alder reaction.
- Nakajima, Hideto,Yasuda, Makoto,Chiba, Kouji,Baba, Akio
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supporting information; experimental part
p. 4794 - 4796
(2010/08/22)
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- Synthesis of (±)-diospongin a: A hetero-diels-alder and c-glycosylation approach
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The racemic natural product diospongin A has been prepared using a short and stereoselective sequence. Key steps include a hetero-Diels-Alder reaction and an anchimeric assistance-controlled C-glycosylation. Georg Thieme Verlag Stuttgart · New York.
- More, Jesse D.
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experimental part
p. 2419 - 2423
(2010/09/18)
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- Rapid synthesis of carbohydrate derivatives, including mimetics of C-linked disaccharides and C-linked aza disaccharides, using the hetero-Diels-Alder reaction
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In this work we demonstrate the value of performing a hetero-Diels-Alder reaction (HDAR) between Danishefsky's diene and a range of aldehydes or imines, under microwave irradiation. By using a range of aldehydes and imines, including those derived from carbohydrates, access to functionalized 2,3-dihydro-4H- pyran-4-ones or 2,3-dihydro-4-pyridinones in good to excellent synthetic yields is possible. A particular strength of the methodology is its ability to access mimetics of C-linked disaccharides and C-linked aza disaccharides, targets of current therapeutic interest, in a rapid, convenient, and diastereoselective manner. The effect of high pressure on the HDARs involving carbohydrate-derived aldehydes and imines is also explored, with enhancement in yields occurring for the aldehyde substrates. Finally, HDARs using carbohydrate derived ketones, enones, and enals are described under a range of conditions. Optimum results were obtained under high-pressure conditions, with highly functionalized carbohydrate derivatives being afforded, in good yields, in this way.
- Burland, Peter A.,Coisson, David,Osborn, Helen M. I.
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supporting information; experimental part
p. 7210 - 7218
(2011/02/22)
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- Highly enantioselective hetero-Diels-Alder reactions between Rawal's diene and aldehydes catalyzed by chiral dirhodium(ii) carboxamidates
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The first example of a chiral Lewis acid-catalyzed enantioselective hetero-Diels-Alder (HDA) reaction between 1-dimethylamino-3-silyloxy-1,3- butadiene (Rawal's diene) and aldehydes is described. The cycloaddition reaction under the influence of 1 mol% of
- Watanabe, Yudai,Washio, Takuya,Shimada, Naoyuki,Anada, Masahiro,Hashimoto, Shunichi
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supporting information; experimental part
p. 7294 - 7296
(2010/06/13)
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- Origin of the asymmetric induction in metallosalen-catalyzed reactions of aldehydes
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This study investigates, experimentally and computationally, the role played by the structure of the diamine moiety of salen chromium complexes in determining the catalyst conformational equilibrium and, in consequence, the direction of asymmetric induction in metallosalen-catalyzed reactions of aldehydes. The Royal Society of Chemistry 2009.
- Chaiadaj, Wojciech,Jurczak, Janusz
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supporting information; experimental part
p. 6747 - 6749
(2010/03/25)
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- Heterogeneous Lewis acid catalysis with self-organized polymeric rare earth arylsulfonates under solvent-free conditions
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Polymeric rare earth arylsulfonates, easily prepared from rare earth triisopropoxides and biphenyl-4,4'-disulfonic acid (BPDSA) or 1,3,5-triphenylbenzene trisulfonic acid (TPTSA) in a self-organization manner, were found to work as an efficient heterogene
- Furuno, Hiroshi,Ishida, Shuichi,Suzuki, Shoko,Hayano, Tetsuji,Onitsuka, Satoaki,Inanaga, Junji
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experimental part
p. 1007 - 1018
(2010/10/03)
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- Chromium-thiophene-salen-based polymers for heterogeneous asymmetric hetero-Diels-Alder reactions
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New chiral thiophene-salen ligands have been synthesized and the corresponding chromium complexes proved to be efficient catalysts for promoting asymmetric hetero-Diels-Alder reactions with good activities and high enantio-selectivities (up to 88% ee). Th
- Zulauf, Anais,Mellah, Mohamed,Guillot, Regis,Schulz, Emmanuelle
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experimental part
p. 2118 - 2129
(2009/04/11)
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- Asymmetric hetero Diels-Alder reaction catalyzed by chromium complexes of heterogeneously hybridized salen/salan ligands
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Various heterogeneously or homogeneously hybridized salen/salan ligands were synthesized, and study of hetero Diels-Alder reactions using their chromium complexes as catalysts revealed that a well-designed heterogeneously hybridized ligand serves as a chi
- Eno, Satomi,Egami, Hiromichi,Uchida, Tatsuya,Katsuki, Tsutomu
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p. 632 - 633
(2008/12/20)
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- A novel chiral H′4-NOBIN schiff base for hetero-diels-alder reaction of danishefsky's diene with aldehydes
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Novel chiral H′4-NOBIN was synthesized in 66% yield through partial hydrogenation of 2-amino-2′-hydroxy-1,1′-binaphthyl, and the structure was proved via X-ray analysis of its salicylaldehyde Schiff base, which was tested in the enantioselectiv
- Li, Xinsheng,Meng, Xiangyan,Su, Hong,Wu, Xiaohua,Xu, Dongcheng
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p. 857 - 860
(2008/12/22)
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- Cationic chiral dirhodium carboxamidates are activated for lewis acid catalysis
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(Chemical Equation Presented) The power of a positive charge: Oxidized chiral dirhodium carboxamidate salts increase the rate of reaction of selected aldehydes with the Danishefsky diene (hetero-Diels-Alder reaction) and with nitrones (1,3-dipolar cycload
- Wang, Yuanhua,Wolf, Joffrey,Zavalij, Peter,Doyle, Michael P.
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p. 1439 - 1442
(2008/12/23)
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- BINOlate-magnesium catalysts for enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with aldehydes
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An efficient catalytic enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with aldehydes using the magnesium binaphthoxide system has been developed, affording a variety of 2-substituted 2,3-dihydro-4H-pyran-4-ones in high yields and with
- Du, Haifeng,Zhang, Xue,Wang, Zheng,Bao, Hongli,You, Tianpa,Ding, Kuiling
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scheme or table
p. 2248 - 2254
(2009/04/08)
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- Cleft molecules as organocatalysts in an asymmetric hetero-Diels-Alder reaction
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The synthesis and application of chiral carbocyclic cleft molecules derived from 2,3:6,7-dibenzobicyclo[3.3.1]nona-2,6-diene-4,8-dione in the hetero-Diels-Alder reaction of benzaldehydes and aminodiene 14 is presented. Catalysis by single hydrogen-bond ac
- Friberg, Annika,Olsson, Cecilia,Ek, Fredrik,Berg, Ulf,Frejd, Torbjoern
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p. 885 - 891
(2008/02/08)
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- Methods of performing cycloadditions, reaction mixtures, and methods of performing asymmetric catalytic reactions
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Methods of performing cycloadditions are described that include (a) combining a first reactant and a second reactant in a hydrogen bonding solvent to form a reaction mixture; and (b) reacting the first reactant and the second reactant to form a cycloadduc
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Page/Page column 23-24; 33-34
(2010/11/27)
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- Storable, powdered chiral zirconium complex for asymmetric aldol and hetero Diels-Alder reactions
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A storable, powdered chiral zirconium catalyst for asymmetric aldol and hetero Diels-Alder reactions has been developed. The catalyst has the same activity as that prepared in situ even after being stored for 3 months. Moreover, this chiral Zr catalyst wo
- Seki, Kazutaka,Ueno, Masaharu,Kobayashi, Shu
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p. 1347 - 1350
(2008/01/01)
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- Systematically probing the effect of catalyst acidity in a hydrogen-bond-catalyzed enantioselective reaction
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(Chemical Equation Presented) Defining the relationship: The effect of catalyst acidity has been systematically probed by using a modular oxazoline catalyst in a hetero-Diels-Alder reaction catalyzed by hydrogen bonding. Linear free energy relationships w
- Jensen, Katrina H.,Sigman, Matthew S.
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p. 4748 - 4750
(2008/02/10)
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- Experimental and theoretical studies on the hydrogen-bond-promoted enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with benzaldehyde
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The enantioselective hetero-Diels-Alder (HDA) reaction of Danishefsky's diene with benzaldehyde has been achieved catalytically by a series of α,α,α′,α′-tetraaryl-1,3-dioxolane-4, 5-dimethanol (TADDOL) derivatives through hydrogen-bonding activation, affo
- Zhang, Xue,Du, Haifeng,Wang, Zheng,Wu, Yun-Dong,Ding, Kuiling
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p. 2862 - 2869
(2007/10/03)
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- Chiral chromium(III) porphyrins as highly enantioselective catalysts for Hetero-Diels-Alder reactions between aldehydes and dienes
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Starting from enantiomerically pure 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2, 3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracene-9-yl]porphyrin, treatment with CrCl2 and subsequent air oxidation afforded the corresponding Cr(III) complex, with chlo
- Berkessel, Albrecht,Ertuerk, Erkan,Laporte, Cecile
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p. 223 - 228
(2007/10/03)
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- Polyglycerol-supported chromium-salen as a high-loading dendritic catalyst for stereoselective Diels-Alder reactions
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In this paper we demonstrate the application of hyperbranched polyglycerol (PG) 3 as a polymeric support for asymmetric catalysis. A new polyglycerol-supported unsymmetrical salen ligand 4 is described, which was successfully purified by gel permeation chromatography (GPC) or by ultrafiltration. After the insertion of the metal, e.g., chromium, the corresponding polymeric chromium complex was used as catalyst for asymmetric Diels-Alder reactions between Danishefsky's diene and benzaldehyde. The catalytic activities (up to 98% conversion) and enantioselectivities (up to 78% ee) were comparable to the original catalyst reported by Jacobsen. The soluble polyglycerol-supported catalysts were recovered by dialysis after the catalytic reactions and were recycled two times to afford identical reactivities as in the first run, with slightly reduced enantioselectivities. Moreover, this polymeric support catalyst showed a high retention (99.02%) in a continuously operated membrane reactor.
- Hajji, Chakib,Roller, Sebastian,Beigi, Maryam,Liese, Andreas,Haag, Rainer
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p. 1760 - 1771
(2007/10/03)
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- DIANANE-CrIII-salen complexes as highly enantioselective catalysts for hetero-Diels-Alder reactions of aldehydes with dienes
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A new type of chromium-salen complex bearing DIANANE (endo,endo-2,5- diaminonorbornane) as chiral backbone has been synthesized and applied to the hetero-Diels-Alder reaction of Danishefsky's diene with various aldehydes. The reactions afford the correspo
- Berkessel, Albrecht,Vogl, Nadine
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p. 5029 - 5035
(2007/10/03)
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- A convenient and versatile approach to 2,3-dihydro-4H-pyran-4-ones via tandem aldol reaction-conjugate addition
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Aldol reaction of enones 1a-c with aldehydes followed by intramolecular conjugate addition proceeded smoothly to afford corresponding 2,3-dihydro-4H-pyran-4-ones in high yields under mild conditions.
- Gao, Bo,Yu, Zhipeng,Fu, Zhengyan,Feng, Xiaoming
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p. 1537 - 1539
(2007/10/03)
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- A Lewis Base-catalyzed hetero Diels-Alder reaction between aldehydes and the Danishefsky's diene
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A lithium methoxide-catalyzed hetero Diels-Alder reaction of aromatic and aliphatic aldehydes with 1-methoxy-3-trimethylsilyloxy-1,3-butadiene (Danishefsky's diene) is described. It proceeds through the Mukaiyama-Aldol reaction pathway and affords the cor
- Mukaiyama, Teruaki,Kitazawa, Takayuki,Fujisawa, Hidehiko
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p. 328 - 329
(2007/10/03)
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- Hetero diels-alder type reactions between danishefsky's dienes in the presence of lewis base catalysts. An efficient method for the synthesis of substituted 2,3-dihydropyran-4-ones
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Alkoxy anion such as methoxide anion works effectively as Lewis base catalyst to activate silicon-carbon bond of 1-methoxy-3-trimethylsilyloxy-1,3-butadiens (Danishefsky's dienes) in the reaction between aldehydes and ketones. By using Lewis base as catal
- Kitazawa, Takayuki,Mukaiyama, Teruaki
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p. 417 - 427
(2008/02/09)
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- One catalyst for two distinct reactions: Sequential asymmetric hetero Diels-Alder reaction and diethylzinc addition
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This paper describes the successful development of a series of chiral zinc catalysts containing (R)-3,3′-Br2-BINOL ligand and various diimine activators for enantioselective HDA reaction of Danishefsky's diene with aldehydes through a combinato
- Du, Haifeng,Zhang, Xue,Wang, Zheng,Ding, Kuiling
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p. 9465 - 9477
(2007/10/03)
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- Design of hydrogen bond catalysts based on a modular oxazoline template: Application to an enantioselective hetero Diels-Alder reaction
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(Chemical Equation Presented) A catalyst system that displays two hydrogen bond donating arms from a rigid oxazoline backbone and its utility in a hydrogen bond promoted enantioselective hetero Diels-Alder reaction are described.
- Rajaram, Sridhar,Sigman, Matthew S.
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p. 5473 - 5475
(2007/10/03)
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