- Tetra-Aza-Pentacenes by means of a One-Pot Friedl?nder Synthesis
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Tetra-aza-pentacenes are attractive n-type small molecules for optoelectronic device applications, yet their syntheses are often laborious. Disclosed here is a one-pot Friedl?nder synthesis of 1,7,8,14-tetraazapentacece (tAP) derivatives (linear and/or be
- Ukwitegetse, Narcisse,Saris, Patrick J. G.,Sommer, Jonathan R.,Haiges, Ralf M.,Djurovich, Peter I.,Thompson, Mark E.
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- An Isolable Silicon Analogue of a Ketone that Contains an Unperturbed Si=O Double Bond
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Despite tremendous efforts to synthesize isolable compounds with an Si=O bond, silicon analogues of ketones that contain an unperturbed Si=O bond have remained elusive for more than 100 years. Herein, we report the synthesis of an isolable silicon analogu
- Kobayashi, Ryo,Ishida, Shintaro,Iwamoto, Takeaki
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- Gold(I)-Catalyzed 7-exo-dig Cyclization: A Key Step to Access the Bicyclo[4.2.1]nonane Skeleton of Vibsatin A, a Neurotrophic Diterpenoid
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Vibsatin A is a new neurotrophic vibsane-Type diterpenoid comprising a bridged bicyclo[4.2.1]nonane skeleton. Inspired by Sawamura's works, we generated the bicyclic backbone through a Conia-ene-derived 7-exo-dig cyclization from an enantiomerically enriched TIPS-based silyl enol ether. The reaction, catalyzed by a sensitive gold(I) complex, was efficiently performed on a large scale by glovebox free techniques. Furthermore, the shape of this system was exploited for subsequent installation of all of the stereogenic centers.
- Allievi, Luca,Dhambri, Sabrina,Sun, Rongyu,Selkti, Mohamed,Lannou, Marie-Isabelle,Sorin, Geoffroy,Ardisson, Janick
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- Highly Stereoselective Synthesis of 1,2-Disubstituted Indanes by Pd-Catalyzed Heck/Suzuki Sequence of Diarylmethyl Carbonates
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A palladium-catalyzed Mizoroki-Heck-type cyclization/Suzuki-Miyaura cross-coupling cascade of diarylmethyl carbonates with arylboronic acid derivatives has been developed to deliver the corresponding 1,2-disubstituted indanes in good yields with high dias
- Matsude, Akihiro,Hirano, Koji,Miura, Masahiro
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- Boraformylation and Silaformylation of Allenes
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The boraformylation of allenes with B2(pin)2and a formate ester as boron and formyl source, respectively, proceeds in the presence of a copper catalyst. The reaction selectively affords the corresponding β-boryl β,γ-unsaturated aldeh
- Fujihara, Tetsuaki,Sawada, Ayumi,Yamaguchi, Tatsuya,Tani, Yosuke,Terao, Jun,Tsuji, Yasushi
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Read Online
- Preparation method of 2, 6-di-tert-butyl-4-bromoanisole
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The invention provides a preparation method of 2, 6-di-tert-butyl-4-bromoanisole, which comprises the following steps of: adding a tert-butylation reagent into 4-bromoanisole under the catalysis of acid, and reacting to obtain 2, 6-di-tert-butyl-4-bromoanisole. According to the preparation method disclosed by the invention, 4-bromoanisole which is cheap and easy to obtain is taken as a raw material, a solvent is not required to be used, the 2, 6-di-tert-butyl-4-bromoanisole can be obtained only in one step, the preparation method has the advantages of high production efficiency and low production cost, and the raw materials and auxiliary reagents used in the reaction process are relatively low in toxicity and are more environment-friendly.
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Paragraph 0073-0081
(2021/11/06)
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- Phospholane-Phosphite Ligands for Rh Catalyzed Enantioselective Conjugate Addition: Unusually Reactive Catalysts for Challenging Couplings
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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
- Clarke, Matthew L.,Cordes, David B.,Fuentes, José A.,Gilbert, Sophie H.,Slawin, Alexandra M. Z.
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supporting information
(2020/05/25)
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- COMPOSITIONS AND METHODS FOR IMMUNE MODULATION AND TREATMENT OF CANCER
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The disclosure relates to rexinoids, including compounds of the Formula (I) and (II) or a pharmaceutically acceptable salt, polymorph, prodrug, solvate or clathrate thereof. These rexinoids are useful for increasing PD-L1 in vivo, for treatment of cancer, and for inhibiting the onset of cancer.
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Paragraph 0191
(2020/07/31)
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- Chiral 1,3-diaryl imidazolium salt carbene precursor, synthesis method thereof, metal salt compound and application
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The invention discloses a chiral 1,3-diaryl imidazolium salt carbene precursor, a synthesis method thereof, a metal salt compound and application. The chiral 1,3-diaryl imidazolium salt carbene precursor forms a complex together with the copper to catalyz
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Paragraph 0375-0379
(2019/06/07)
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- Formation and Activation of Zr/Hf Bis(phenolate-ether) Precatalysts
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Zr and Hf complexes of bis(phenolate-ether) (“O4”) ligands feature high activity, stereoselectivity and molecular weight capability for propene polymerization at high temperature. Here we report a simplified ligand synthesis and several new examples of O4
- Cuthbert, Eric N. T.,Busico, Vincenzo,Herbert, David E.,Budzelaar, Peter H. M.
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supporting information
p. 3396 - 3410
(2019/08/12)
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- Enantioselective Alkylation of 2-Oxindoles Catalyzed by a Bifunctional Phase-Transfer Catalyst: Synthesis of (?)-Debromoflustramine B
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A new bifunctional phase-transfer catalyst that employs hydrogen bonding as a control element was developed to promote efficient enantioselective SN2 reactions for the construction all-carbon quaternary stereocenters in high yield and excellent enantioselectivity (up to 97 % ee) utilizing the alkylation of a malleable oxindole substrate. The utility of the methodology was demonstrated through a concise and highly enantioselective synthesis of (?)-debromoflustramine B.
- Craig, Ryan,Sorrentino, Emiliano,Connon, Stephen J.
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supporting information
p. 4528 - 4531
(2018/03/21)
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- Enantioselective Rhodium-Catalyzed Atom-Economical Macrolactonization
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A highly attractive route toward macrolactones, which form the cyclic scaffold of a multitude of diverse natural compounds, is described. Although many chemical approaches to this structural motif have been explored, an asymmetric variant of the cyclization is unprecedented. Herein we present an enantioselective macrolactonization through an intramolecular atom-economical rhodium-catalyzed coupling of ω-allenyl-substituted carboxylic acids. The use of a modified diop ligand, chiral DTBM-diop, led to high enantioselectivity (up to 93 % ee). The reaction tolerated a large variety of functionalities, including α,β-unsaturated carboxylic acids and depsipeptides, and provided the desired macrocycles with very high enantio- and diastereoselectivity.
- Ganss, Stephanie,Breit, Bernhard
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supporting information
p. 9738 - 9742
(2016/08/10)
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- Distance dependence of bidirectional concerted proton-electron transfer in phenol-ru(2,2'-bipyridine)32+ dyads
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Proton-coupled electron transfer (PCET) was investigated in three covalent donor-bridge-acceptor molecules with different bridge lengths. Upon photoexcitation of their Ru(bpy)32+ (bpy=2,2,-bipyridine) photosensitizer in acetonitrile, intramolecular long-range electron transfer from a phenolic unit to Ru(bpy)32+ occurs in concert with release of the phenolic proton to pyrrolidine base. The kinetics of this bidirectional concerted proton-electron transfer (CPET) reaction were studied as a function of phenol-Ru(bpy)32+ distance by increasing the number of bridging p-xylene units. A distance decay constant (β) of 0.67±0.23 A-1 was determined. The distance dependence of the rates for CPET is thus not significantly steeper than that for ordinary (i.e., not proton coupled) electron transfer across the same bridges, despite the concerted motion of oppositely charged particles into different directions. Long-range bidirectional CPET is an important reaction in many proteins and plays a key role in photosynthesis; our results are relevant in the context of photoinduced separation of protons and electrons as a means of light-to-chemical energy conversion. This is the first determination of β for a bidirectional CPET reaction. Time for a concert! The dependence of the rates for bidirectional concerted proton-electron transfer (CPET) on the electron donor/electron acceptor distance was determined for the first time (see scheme). The results are relevant in the context of photodriven separation of protons and electrons across natural or artificial membranes as a means of light-to-chemical energy conversion.
- Chen, Jing,Kuss-Petermann, Martin,Wenger, Oliver S.
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supporting information
p. 4098 - 4104
(2014/04/17)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE CYCLOPROPANE CARBOXYLIC ACID ESTER COMPOUND, ASYMMETRIC COPPER COMPLEX, AND OPTICALLY ACTIVE SALICYLIDENEAMINOALCOHOL COMPOUND
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A process for producing an optically active cyclopropanecarboxylic acid ester compound represented by the formula (4): (wherein R5, R6 and * each represents the same meaning as defined below), comprising reacting a diazoacetic acid e
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Page/Page column 24
(2011/07/29)
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- Easier preparation of 2,6-Di-tert-butylphenyl derivatives 1
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Despite steric shielding by the 2,6-di-tert-butylphenyl group (super-2,6-xylyl=xyl*), inexpensive sodium phenolate (xyl*-ONa) reacts with dimethyl sulfate to produce only xyl*-OCH3 (94%) with complete suppression of the alternative 4-methylation. Reductive cleavage of xyl*-OCH3 by elemental lithium with the help of an electron carrier generates xyl*-Li, which in turn yields xyl*-CO2H (63%). The corresponding 4-methyl-derivatives of these compounds were obtained analogously. The acid chloride xyl*-COCl (77% yield) acylates HalMgCH 2R to give only xyl*-COCH3 (86%) or xyl*-COEt (97%). These two ketones react with n-butyllithium (no carbonyl addition) and Cl-PO(OEt)2 to furnish only the enol phosphates xyl*-C(=CH 2)OPO(OEt)2 (84%) or xyl*-C(=CHCH 3)OPO(OEt)2 (up to 70%), respectively. Only 1,2-elimination occurs when the latter two products are treated with tert-butyllithium, affording xyl*-CCH (68%) or xyl*-CCMe (88%), respectively. Georg Thieme Verlag Stuttgart - New York.
- Knorr, Rudolf,Rossmann, Eva Christine,Knittl, Monika
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scheme or table
p. 2124 - 2128
(2010/09/04)
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- Pyridine, Pyrimidine and Pyrazine Derivatives as Cxcr3 Receptor Modulators
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The invention encompasses compounds of Formula I or pharmaceutically acceptable salts thereof, which are modulators of the CXCR3 chemokine receptor function useful for the treatment or prevention of pathogenic inflammatory processes, autoimmune diseases o
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Page/Page column 15
(2009/02/11)
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- Syntheses of sterically hindered zwitterionic pyridinium phenolates as model compounds in nonlinear optics
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Pyridinium phenolates possess a dissymmetric delocalised π-electron system providing a huge quadratic nonlinearity. They are a promising class of molecules for applications in photoelectronics and photonics. Semiempirical calculations indicate that the interplanar angle between the two aromatic rings leads to enhancement in the NLO properties of these compounds. The confirmation of this feature may be provided by the study of a new series of sterically hindered pyridinium phenolates 2a-e bearing two tert-butyl substituents at the ortho position(s) of the phenolate functionality. Such bulky groups would enhance the solubility of zwitterions in organic solvents and would limit the formation of aggregates. Their efficient preparations by using Suzuki cross-coupling reactions involving 3,5-dialkylated 4-bromopyridine N-oxides are described herein. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Diemer, Vincent,Chaumeil, Helene,Defoin, Albert,Fort, Alain,Boeglin, Alex,Carre, Christiane
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experimental part
p. 1767 - 1776
(2009/04/11)
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- Mapping the active site in a chemzyme: Diversity in the N-substituent in the catalytic asymmetric aziridination of imines
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(Chemical Equation Presented) The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)3 is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.
- Zhang, Yu,Lu, Zhenjie,Desai, Aman,Wulff, William D.
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supporting information; experimental part
p. 5429 - 5432
(2009/06/20)
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- Convenient divergent strategy for the synthesis of TunePhos-type chiral diphosphine ligands and their applications in highly enantioselective Ru-catalyzed hydrogenations
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(Chemical Equation Presented) A convenient, divergent strategy for the synthesis of a series of modular and fine-tunable C3-TunePhos-type chiral diphosphine ligands and their applications in highly efficient Rucatalyzed asymmetric hydrogenations were explored. Up to 97 and 99% ee values were achieved for the enantioselective synthesis of β-methyl chiral amines and α-hydroxy acid derivatives, respectively.
- Sun, Xianfeng,Zhou, Le,Li, Wei,Zhang, Xumu
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p. 1143 - 1146
(2008/09/18)
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- Using triethynylphosphine ligands bearing bulky end caps to create a holey catalytic environment: Application to gold(I)-catalyzed alkyne cyclizations
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The synthesis, properties and catalytic uses of phosphinoalkynes bearing bulky end caps at the alkyne termini, that is, tris[(triarylsilyl)ethynyl]phosphines are reported. The most salient feature of the new phosphines is the holey molecular shape possess
- Ochida, Atsuko,Ito, Hideto,Sawamura, Masaya
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p. 16486 - 16487
(2007/10/03)
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- TRANSITION METAL COMPLEX HAVING DIPHOSPHINE COMPLEX AS LIGAND
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A transition metal complex having 2,2'-bis[bis(3,5-di-tert-butyl-4-methoxyphenyl)phosphino]-1,1'-binaphthyl as a ligand. The presence of the transition metal complex in the reaction system of an asymmetric reaction system allows the preparation of an objective compound having an objective absolute configuration with improved efficiency.
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Page/Page column 13
(2010/02/13)
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- PROCESS FOR PREPARATION OF DIPHOSPHINE COMPOUNDS AND INTERMEDIATES FOR THE PROCESS
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A production method of a_compound represented by the formula wherein R1a, R1b, R1c, R1d, R1e, R1f, R2a, R2b, R2c R2d, R2e and R2f are the same or different and each is a hydrogen atom and the like, and R3, R4, R5, R6, R7, R8, R9 and R10 are the same or different and each is a hydrogen atom and the like, or a salt thereof, which comprises reacting a compound represented by the formula wherein X is a leaving group and other symbols are as defined above, or a salt thereof, with a phosphine-borane complex represented by the formula wherein the symbols are as defined above, or a salt thereof, in a solvent in the presence of an amine and a nickel catalyst, is provided.
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