- Crossed Regio- and Enantioselective Iron-Catalyzed [4+2]-Cycloadditions of Unactivated Dienes
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The cyclohexene motif is ubiquitous in nature and specialty chemicals. A straightforward selective access to chiral cyclohexenes from unactivated dienes and dienophiles is not feasible by classical Diels–Alder reaction and constitutes an unsolved syntheti
- Braconi, Elena,Cramer, Nicolai
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supporting information
(2021/12/22)
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- Method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and diphosphine ligand used in method
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The invention discloses a method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and a diphosphine ligand used in the method. According to the invention, indole-substituted phosphoramidite diphosphine ligand which is stable in air and insensitive to light is synthesized by utilizing a continuous one-pot method, and the indole-substituted phosphoramidite diphosphine ligand and a rhodium catalyst are used for jointly catalyzing to successfully achieve a hydroformylation reaction of aromatic terminal alkyne and terminal conjugated eneyne under the condition of synthesis gas for the first time, so that an olefine aldehyde structure compound can be rapidly and massively prepared, and particularly, a polyolefine aldehyde structure compound which is more difficult to synthesize in the prior art can be easily prepared and synthesized, and a novel method is provided for synthesis and modification of drug molecules, intermediates and chemical products.
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Paragraph 0133-0136
(2021/05/29)
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- Asymmetric Synthesis of Functionalized 9-Methyldecalins Using a Diphenylprolinol-Silyl-Ether-Mediated Domino Michael/Aldol Reaction
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Substituted 9-methyldecalin derivatives containing an all carbon quaternary chiral center were synthesized with excellent enantioselectivity via an organocatalyst-mediated domino reaction. The first reaction is a diphenylprolinol silyl ether-mediated Michael reaction, and the second reaction is an intramolecular aldol reaction. The enantiomerically pure catalyst is involved in both reactions.
- Hayashi, Yujiro,Salazar, Hugo A.,Koshino, Seitaro
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p. 6654 - 6658
(2021/09/11)
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- Cyanine-Like Boronic Acid-Derived Salicylidenehydrazone Complexes (Cy-BASHY) for Bioimaging Applications
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Boronic acid-derived salicylidenehydrazone complex (BASHY) dyes with a polymethine backbone were designed to yield efficient red-emitting and two-photon absorbing fluorophores that can be used as markers for astrocytes. The dyes are chemically stable in aqueous solution and do not undergo photodecomposition. Their photophysical properties can be electronically fine-tuned and thereby adapted to potentially different imaging situations and requirements.
- Santos, Fábio M. F.,Domínguez, Zoe,Fernandes, Jo?o P. L.,Parente Carvalho, Cátia,Collado, Daniel,Pérez-Inestrosa, Ezequiel,Pinto, Maria V.,Fernandes, Adelaide,Arteaga, Jesús F.,Pischel, Uwe,Gois, Pedro M. P.
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supporting information
p. 14064 - 14069
(2020/10/06)
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- Evolution of physical and photocatalytic properties of new Zn(II) and Ru(II) complexes
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Synthesis of Zn(II) and Ru(II) complexes were reported by using N4-macrocyclic Schiff base ligands under solvothermal conditions. The newly synthesized Zn(II) and Ru(II) complexes have been characterized by various physico-chemical techniques such as elemental analysis, molar conductance, HRMS, TGA, FESEM, UV–Vis, FT-IR, 1H NMR, and cyclic voltammetry. By using molar conductance studies, the complexes are formulated as [Zn(TPTTP)]Cl2 and [Ru(TPTTP)Cl2]. C–H bond activation of an sp3 group of methylstyrenes (converted into cinnamaldehydes) and C–H bond activation of the sp2 bond of polycyclic aromatic hydrocarbons through photooxidation was examined in the presence of Zn(II) and Ru(II) complexes. Reusable activity studies and photostability of catalyst are investigated by using UV–Vis spectra. Based on the results, higher catalytic activity of [Ru(TPTTP)Cl2] complex than [Zn(TPTTP)]Cl2 complex in both C–H bond activation and photooxidation of aromatic hydrocarbons has been reported.
- Gugulothu, Venkanna,Ahemed, Jakeer,Subburu, Mahesh,Yadagiri, Bhongiri,Mittal, Ritu,Prabhakar, Chetti,Pola, Someshwar
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p. 412 - 423
(2019/06/27)
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- Highly Enantioselective Synthesis of Functionalized Glutarimide Using Oxidative N-Heterocyclic Carbene Catalysis: A Formal Synthesis of (?)-Paroxetine
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A simple yet highly effective approach toward enantioselective synthesis of trans-3,4-disubstituted glutarimides from readily available starting materials is developed using oxidative N-heterocyclic carbene catalysis. The catalytic reaction involves a formal [3 + 3] annulation between enals and substituted malonamides enabling the production of glutarimide derivatives in a single chemical operation via concomitant formation of C-C and C-N bonds. The reaction offers easy access to a broad range of functionalized glutarimides with excellent enantioselectivity and good yield. Synthetic application of the method is demonstrated via formal synthesis of (?)-paroxetine and other bioactive molecules.
- Porey, Arka,Santra, Surojit,Guin, Joyram
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p. 5313 - 5327
(2019/04/16)
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- Enantioselective Organocatalytic Enamine C?H Oxidation/Diels- Alder Reaction
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α,β-unsaturated aldehydes have been traditionally used in LUMO lowering asymmetric aminocatalysis (iminium catalysis), while the use of saturated aldehydes as substrates in this type of catalysis has been elusive, until recently. Herein, we demonstrate that organic, single-electron oxidants in the presence of diarylprolinol silylether type catalysts serve as effective tools for the transformation of electron rich enamines to iminium ions which partake in a subsequent Diels-Alder reaction. This enantioselective one-pot transformation represents the first example of saturated aldehydes being used in domino Diels-Alder reaction processes and demonstrates the power of this protocol for construction of stereo-defined chiral compounds and building blocks. (Figure presented.).
- D?ambaski, Zdravko,Tzaras, Dimitrios-Ioannis,Lee, Sunggi,Kokotos, Christoforos G.,Bondzic, Bojan P.
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supporting information
p. 1792 - 1797
(2019/02/25)
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- Dehydrogenative Synthesis of Linear α,β-Unsaturated Aldehydes with Oxygen at Room Temperature Enabled by tBuONO
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Synthesis of linear α,β-unsaturated aldehydes via a room-temperature oxidative dehydrogenation has been realized by the cocatalysis of an organic nitrite and palladium with molecular oxygen as the sole clean oxidant. Linear α,β-unsaturated aldehydes could be efficiently prepared under aerobic catalytic conditions directly from the corresponding saturated linear aldehydes. Besides linear products, the aromatic analogy could also be smoothly achieved by the same standard method. The organic nitrite redox cocatalyst and alcohol solvent play a key role for realizing this method.
- Wang, Mei-Mei,Ning, Xiao-Shan,Qu, Jian-Ping,Kang, Yan-Biao
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p. 4000 - 4003
(2017/06/19)
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- Enantioselective Intermolecular Addition of Aliphatic Amines to Acyclic Dienes with a Pd-PHOX Catalyst
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We report a method for the catalytic, enantioselective intermolecular addition of aliphatic amines to acyclic 1,3-dienes. In most cases, reactions proceed efficiently at or below room temperature in the presence of 5 mol % of a Pd catalyst bearing a PHOX ligand, generating allylic amines in up to 97:3 er. The presence of an electron-deficient phosphine within the ligand not only leads to a more active catalyst but also is critical for achieving high site selectivity in the transformation.
- Adamson, Nathan J.,Hull, Ethan,Malcolmson, Steven J.
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p. 7180 - 7183
(2017/06/05)
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- One-Pot Synthesis of (S)-Baclofen via Aldol Condensation of Acetaldehyde with Diphenylprolinol Silyl Ether Mediated Asymmetric Michael Reaction as a Key Step
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An efficient asymmetric total synthesis of (S)-baclofen was accomplished via a one-pot operation from commercially available materials using sequential reactions, such as aldol condensation of acetaldehyde, diphenylprolinol silyl ether mediated asymmetric Michael reaction of nitromethane, Kraus-Pinnick oxidation, and Raney Ni reduction. Highly enantioenriched baclofen was obtained in one pot with a good yield over four reactions.
- Hayashi, Yujiro,Sakamoto, Daisuke,Okamura, Daichi
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supporting information
p. 4 - 7
(2016/01/15)
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- Base directed palladium catalysed Heck arylation of acrolein diethyl acetal in water
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The selective Heck arylation of acrolein diethyl acetal catalysed by [Pd(NH3)4]Cl2 in the presence of RAME-β-CD in water as solvent is described. Depending on the base (i.e. NaOAc or HN(i-Pr)2) good to high selectivity's towards, respectively, the cinnamaldehydes 2 or the 3-arylpropionic esters 1 were achieved. The results support that depending on the base different palladium intermediate complexes are formed. Using NaOAc, {[ArPdX(H2O)2]} complex is preferentially generated giving the cinnamaldehyde 2. On the other hand, in the presence of HN(i-Pr)2, a L-type ligand, [ArPdX(HN(i-Pr) 2(H2O)] or [ArPdX(HN(i-Pr)2(HN(i-Pr) 2)] will be generated leading to the formation of the 3-arylpropionic ester 1. For the last, coordinated amine participates very probably to the formation of the esters through intramolecular syn β-H elimination.
- Al-Maksoud, Walid,Menuel, Stéphane,Jahjah, Mohamad,Monflier, Eric,Pinel, Catherine,Djakovitch, Laurent
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p. 250 - 258
(2013/11/19)
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- Fluorous oxime palladacycle: A precatalyst for carbon-carbon coupling reactions in aqueous and organic medium
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To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for a wide range of carbon-carbon bond formation reactions (Suzuki-Miyaura, Sonogashira, Stille, Heck, Glaser-type, and Kumada) in either aqueous or organic medium under microwave irradiation. Palladacycle 1 could be recovered through F-SPE in various coupling reactions with recovery ranging from 84 to 95% for the first cycle. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses of the Pd content in the crude product from each class of transformation indicated extremely low levels of leaching and the palladacycle could be reused four to five times without significant loss of activity.
- Susanto, Woen,Chu, Chi-Yuan,Ang, Wei Jie,Chou, Tzyy-Chao,Lo, Lee-Chiang,Lam, Yulin
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p. 2729 - 2742
(2012/05/21)
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