- A Chiral, Dendralenic C-H Acid
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We report the synthesis of a chiral dendralenic C H acid, which contains three unsubstituted binaphthyl moieties. This motif and an achiral variant can be made from their corresponding bis(sulfone) precursors in one step. Despite the presence of the enantiopure binaphthyl backbone, the newly designed chiral C H acid showed only poor enantioselectivity in a Mukaiyama aldol reaction. First attempts toward the synthesis of 3,3'-hexasubstituted binaphthyl-based dendralenic acids are also reported.
- H?fler, Denis,List, Benjamin
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supporting information
p. 38 - 39
(2021/12/29)
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- Photocatalyzed E→Z Contra-thermodynamic Isomerization of Vinyl Boronates with Binaphthol
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The photocatalytic contra-thermodynamic E→Z isomerization of vinyl boronates by using a binaphthol catalyst is disclosed. The reaction, based on the transient formation of a suitable chromophore with a BINOL derivative as the catalyst, allowed geometrical isomerization in good-to-excellent Z/E ratio and excellent-to-quantitative yields. The mechanism of this E→Z contra-thermodynamic isomerization was studied, and the formation of a transient chromophore species is suggested.
- Brégent, Thibaud,Bouillon, Jean-Philippe,Poisson, Thomas
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supporting information
p. 13966 - 13970
(2021/08/25)
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- Method for preparing substituted thiophenol and heterocyclic thiophenol by continuous flow reactor
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The invention relates to a method for preparing substituted thiophenol and heterocyclic thiophenol by a continuous flow reactor. Phenol and phenol derivatives or heterocyclic phenol are taken as starting materials, and target compounds are prepared by four-step reactions of chlorination, esterification, rearrangement and hydrolysis, wherein the rearrangement reaction is conducted in the continuousflow reactor. According to the method, the reaction is guaranteed by a miniaturized heating device for high-temperature reaction and heat generated by the reaction, the conversion rate and the yieldhigher than those in the conventional reactor are obtained in the short residence time of tens of seconds, relevant side reactions are reduced, meanwhile, fluctuation of temperature and concentrationis avoided in the reaction process, temperature run-away and overheat are avoided, and the reaction process is safe and controllable.
- -
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Paragraph 0093-0094; 0097-0098
(2019/01/14)
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- In situ reaction monitoring reveals a diastereoselective ligand exchange reaction between the intrinsically chiral Au38(SR)24 and chiral thiols
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The ligand exchange reaction between racemic Au38(2-PET) 24 (2-PET = 2-phenylethylthiolate) clusters and enantiopure 1,1′-binaphthyl-2,2′-dithiol (BINAS) was monitored in situ using a chiral high-performance liquid chromatography app
- Knoppe, Stefan,Azoulay, Raymond,Dass, Amala,Bürgi, Thomas
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supporting information
p. 20302 - 20305
(2013/03/14)
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- Practical synthetic approach to chiral sulfonimides (CSIs) - Chiral bronsted acids for organocatalysis
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A general approach to the synthesis of optically pure 3,3'diaryl chiral sulfonimides (CSIs) from racemic BINOL has been developed. ortho-Lithiation is directed by the sulfonyl groups, and the resulting dihalides serve as the common precursors for the aryl-substituted CSIs.
- He, Hao,Chen, Ling-Yan,Wong, Wai-Yeung,Chan, Wing-Hong,Lee, Albert W. M.
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supporting information; experimental part
p. 4181 - 4184
(2010/10/02)
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- PROCESS FOR PRODUCTION OF DISULFONIC ACID COMPOUND, ASYMMETRIC MANNICH CATALYST, PROCESS FOR PRODUCTION OF -AMINOCARBONYL DERIVATIVE, AND NOVEL DISULFONATE SALT
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Hexamethylphosphoramide (HMPA) was added to a reaction vessel containing (R)-1,1'-binaphthyl-2,2'-dithiol and potassium hydroxide. The vessel was purged with oxygen and stirred at 80°C for 5 days under 7 atmospheres of oxygen. After being cooled to room temperature, the reaction product was purified to yield potassium (R)-1,1'-binaphthyl-2,2'-disulfonate. The (R)-1,1'-binaphthyl-2,2'-disulfonic acid obtained from the disulfonate and 2,6-diphenylpyridine were stirred in acetonitrile, and then the solvent was evaporated under reduced pressure. Subsequently, magnesium sulfate and distilled CH2Cl2 were added to the reaction product, and the mixture was stirred at room temperature for 30 minutes. The resulting solution was cooled to 0°C. Benzaldehyde imine whose nitrogen is protected with Cbz and subsequently acetyl acetone were dropped into the solution over a period of 1 hour. The resulting mixture was further stirred at 0°C for 30 minutes. A corresponding β-aminocarbonyl derivative was thus produced with an yield of 91% and an enantiomeric excess of 90% ee.
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Page/Page column 7
(2010/08/07)
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- Synthesis of chiral 3,3′-disubstituted 1,1′-binaphthyl-2, 2′-disulfonic acids
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A convenient synthesis of chiral 3,3′-disubstituted 1,1′-binaphthyl-2,2′-disulfonic acids (BINSA, 1) was developed. The key was directed ortho-lithiation of BINSA methyl ester 2 with n-BuLi and subsequent reaction with an electrophile. Electrophiles such as Br2, I2, Me3SiOTf, and i-PrOB(Pin) reacted smoothly with 3,3′-dilithiated BINSA methyl ester, and the corresponding 3,3′-dihalo-, 3,3′-bis(trimethylsilyl)-, and 3,3′-diboryl- BINSA derivatives were obtained in yields of 21-78%. This simple synthetic method is highly attractive since the ability to prepare 3,3′- disubstituted BINOLs in advance can be useful.
- Hatano, Manabu,Sugiura, Yoshihiro,Ishihara, Kazuaki
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scheme or table
p. 1311 - 1314
(2010/11/02)
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- Highly practical BINOL-derived acid-base combined salt catalysts for the asymmetric direct mannich-type reaction
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The catalytic asymmetric direct Mannich-type reaction between aldimines and 1,3-dicarbonyl compounds is one of the most important carbon-carbon bond-forming reactions in organic chemistry. The resulting Mannich adducts can be efficiently transformed into pharmaceutically useful, optically active -amino ketones, -amino esters, -lactams, etc. In the course of our study of chiral acid-base combined salt catalysts for asymmetric reactions, we developed a series of simple, practical, chiral BINOL-derived salt catalysts, such as chiral pyridinium 1,1-binaphthyl-2,2-disulfonates 1, chiral lithium(I) binaphtholate 2, chiral magnesium(II) binaphtholate (3), chiral calcium(II) phosphate 4, and chiral phosphoric acid 5, which were particularly effective for direct Mannich-type reactions. 1 Introduction 2 1,1-Binaphthyl-2,2-disulfonic Acid (BINSA)-Pyridinium Salts 3 Lithium(I) Binaphtholate Salts 4 Magnesium(II) Binaphtholate Salts 5 Calcium(II) Phosphate Salts and Chiral Phosphoric Acids 6 Conclusions. Georg Thieme Verlag Stuttgart · New York.
- Hatano, Manabu,Ishihara, Kazuaki
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scheme or table
p. 3785 - 3801
(2011/02/16)
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- Pyridinium 1,1′-binaphthyl-2,2′-disulfonates as highly effective chiral Br?nsted acid-base combined salt catalysts for enantioselective mannich-type reaction
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We have established, for the first time, a practical synthesis of chiral 1,1′-binaphthyl-2,2′-disulfonic acid (BINSA 1) from inexpensive BINOL. An efficient enantioselective catalysis in the Mannich-type reactions of diketones and ketoester equivalents with aldimines was developed using chiral 1?achiral 2,6-diarylpyridine (2) combined salts, which acted as convenient chiral tailor-made Br?nsted acid?base organocatalysts in situ. Copyright
- Hatano, Manabu,Maki, Toshikatsu,Moriyama, Katsuhiko,Arinobe, Manabu,Ishihara, Kazuaki
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supporting information; experimental part
p. 16858 - 16860
(2009/04/13)
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- Resolution of (1,1'-binaphthalene)-2,2'-dithiol via diastereoisomeric dithioacetals derived from D-glucose
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The efficient resolution of (1,1'-binaphthalene)-2,2'-dithiol has been achieved by the preparation and separation of the chiral diastereoisomeric binaphthalene dithioacetals derived from 2,3,4,5,6-penta-O-methyl-D-glucose followed by transthioacetalization with ethane-1,2-dithiol.
- Bandarage,Painter,Smith
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p. 295 - 300
(2007/10/02)
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- Resolution of (1,1'-Binaphthalene)-2,2'-dithiol by Enzyme Catalysed Hydrolysis of a Racemic Diacyl Derivative
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Both enantiomers of (1,1'-binaphthalene)-2,2'-dithiol (1) can be obtained with 98percent ee by enzymatic (cholesterol esterase) resolution of the corresponding S,S'-dipentanoate.Absolute configuration and enantiomeric purity were determined by crystal structure and 1H NMR analysis, respectively, of a diastereomeric derivative of 1.
- Kiefer, Matthias,Vogel, Rainer,Helmchen, Guenter,Nuber, Bernhard
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p. 7109 - 7114
(2007/10/02)
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- A useful sulfur-transfer reaction with tetrathiomolybdate: Conversion of arylamines to aryl disulfides
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A convenient method for the synthesis of a series of symmetrical aryl disulfides from arylamines via the reaction of their stable diazonium salts with tetrathiomolybdate under anhydrous conditions is described.
- Bhar,Chandrasekaran
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p. 785 - 786
(2007/10/02)
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- Conformational polymorphism and thermorearrangement of 2,2′-bis-O-(N,N-dimethylthiocarbamato)-1,1′-binaphthalene. A facile synthesis of 1,1′-binaphthalene-2,2′-dithiol
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The title compound was found to exhibit conformational polymorphism which greatly influenced the efficiency of the thermorearrangement to 2,2′-bis-S-(N,N-dimethylthiocarbamato)-1,1′-binaphthalene. Recognition of this phenomenon has allowed a reproducible synthesis of 1,1′-binaphthalene-2,2′ dithiol.
- Bandarage, Upul K.,Simpson, Jim,Smith, Robin A. J.,Weavers, Rex T.
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p. 3463 - 3472
(2007/10/02)
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- Preparation of Enantiomerically Pure 1,1'-Binaphthalene-2,2'-diol and 1,1'-Binaphthalene-2,2'-dithiol
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A practical preparation of enantiomerically pure 1,1'-binaphthalene-2,2'-diol (1) and 1,1'-binaphthalene-2,2'-dithiol (2) is reported.Enantiopure 2 is obtained from enantiopure 1 via Newman-Kwart rearrangement of the thiocarbamoyl derivative 5 under controlled reaction conditions.The enantiopure starting diol 1 was obtained by a simple and inexpensive method engaging condensation of thiophosphoryl chloride and (S)-(-)-α-methylbenzylamine in pyridine and reaction of the resulting phosphoramidate 3 with racemic binaphthol 1 to give quantitatively a 1:1 mixture of diasteroisomers 4 that were cleanly separated by a single recrystallization from a chloroform-ethanol mixture in very high yield.The procedures can be scaled up easily.
- Fabbri, Davide,Delogu, Giovanna,Lucchi, Ottorino De
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p. 1748 - 1750
(2007/10/02)
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- Diels-Alder Reactions of 1,2-(1,1'-Binaphthalene-2,2'-diyldisulfonyl)ethylene with Symmetrical and Unsymmetrical Dienes
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The C2-symmetrical chiral reagent 1,2-(1,1'-binaphthalene-2,2'-diyldisulfonyl)ethylene (1) is a reactive dienopile and forms Diels-Alder adducts with symmetrical and unsymmetrical dienes.In the case of unsymmetrical dienes the reaction affords, in most cases, a single diastereomeric adduct whose stereochemistry has been determined by NMR spectroscopy and confirmed by X-ray structure determination of selected adducts.The arylsulfonyl groups can be removed with formation of a double bond, making 1 a chiral synthetic equivalent of acetylene in -cycloaddition reactions.The binaphthyl auxiliary can be recovered and recycled.
- Lucchi, De Ottorino,Fabbri, Davide,Cossu, Sergio
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p. 1888 - 1894
(2007/10/02)
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- Enantioselective oxidation of thioethers. A route to the resolution of -2,2'-dithiol
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A route to the resolution of racemic -2,2'-dithiol 2 is described, involving the transformation of 2 into a series of dithioethers.The latter are subjected to asymmetric oxidation to monosulfoxides by a procedure developed in our laboratory.For some of the thioethers examined the oxidation is highly diastereo- and/or enantioselective.The resolved 2 is then obtained from the optically pure monosulfoxides either by oxidation to the bis-sulfoxides followed by a Pummerer reaction or by a deoxygenation to the dithioether and subsequent reduction.In both cases enantiomerically pure 2 (e.e. > 98percent) was obtained.Keywords: enantioselective oxidation / optical resolution / thioethers / -2,2'-dithiol
- Furia, F. di,Licini, G.,Modena, G.,Valle, G.
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p. 734 - 744
(2007/10/02)
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- ASYMMETRIC OXIDATION OF THIOETHERS. OPTICAL RESOLUTION OF -2,2'-DITHIOL
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Almost optically pure (e.e.>98percent) -2,2'-dithiol (2) is obtained by resolution of racemic 2 via the transformation of the sulfidryl functions into the corresponding thioethers 3 which are asymmetrically oxidized to diastereomeric chiral monosulfoxides 4 and then reconverted into 2.The diastereo and enantioselectivity is dependent on the structure of the thioether; i.e. the dimethylthioether 3a gives two diastereomeric sulfoxides 4a in ca. 1:1 ratio, each of them in >98percent e.e., while cyclic dithioethers 3b-d afford a single diastereomeric sulfoxide 4b-d in 46-78percent e.e..
- Furia, Fulvio Di,Licini, Giulia,Modena, Giorgio,Lucchi, Ottorino De
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p. 2575 - 2576
(2007/10/02)
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- SYNTHESIS OD 1,1'-DIBENZO- AND 1,1'-DINAPHTHO-2,2'-DITHIOLS FROM THE RESPECTIVE THIOPHENES
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The title compounds 1 and 2 were prepared from the respective, inexpensive and readily available thiophenes vis reaction with lithium and sulfur monochloride, followed by reduction with lithium alumoinium hydride.
- Cossu, Sergio,Delogu, Giovanna,Lucchi, Ottorino De,Fabbri, Davide,Fois, Maria Paola
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p. 3431 - 3436
(2007/10/02)
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