- Synthesis and application of N-3,5-dinitrobenzoyl and C3 symmetric diastereomeric chiral stationary phases
-
Three diastereomeric chiral compounds, namely, (R,R)-(+)-2-amino-1,2-diphenylethanol, (1S,2R)-(+)-2-amino-1,2-diphenylethanol, and (1R,2R)-(+)-1,2-diphenylethylenediamine were used as starting materials for preparing three N-3,5-dinitrobenzoyl derivative
- Ryoo, Jae Jeong,Yu, Jeong Jae
-
-
- Copper-Catalyzed Enantioselective Reductive Cross-Coupling of Aldehydes and Imines
-
A copper-catalyzed enantioselective reductive cross-coupling using aromatic aldehydes and imines, producing chiral β-amino alcohols, is described. The catalytic formation of enantioenriched chiral α-alkoxyalkylcopper(I) species from aromatic aldehydes and the subsequent reaction with imine electrophiles are attractive features of this protocol.
- Mitsui, Atsuhisa,Nagao, Kazunori,Ohmiya, Hirohisa
-
supporting information
(2020/02/04)
-
- One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: Theoretical evidence for an asynchronous concerted pathway
-
The one-pot reaction of chlorosulfonyl isocyanate (CSI) with epoxides having phenyl, benzyl and fused cyclic alkyl groups in different solvents under mild reaction conditions without additives and catalysts was studied. Oxazolidinones and five-membered cyclic carbonates were obtained in ratios close to 1:1 in the cyclization reactions. The best yields of these compounds were obtained in dichloromethane (DCM). Together with 16 known compounds, two novel oxazolidinone derivatives and two novel cyclic carbonates were synthesized with an efficient and straightforward method. Compared to the existing methods, the synthetic approach presented here provides the following distinct advantageous: being a one-pot reaction with metal-free reagent, having shorter reaction times, good yields and a very simple purification method. Moreover, using the density functional theory (DFT) method at the M06-2X/6-31+G(d,p) level of theory the mechanism of the cycloaddition reactions has been elucidated. The further investigation of the potential energy surfaces associated with two possible channels leading to oxazolidinones and five-membered cyclic carbonates disclosed that the cycloaddition reaction proceeds via an asynchronous concerted mechanism in gas phase and in DCM.
- Demir, Esra,Sari, Ozlem,?etinkaya, Yasin,Atmaca, Ufuk,Erdem, Safiye Sa?,?elik, Murat
-
p. 1805 - 1819
(2020/11/07)
-
- Alkene Syn- And Anti-Oxyamination with Malonoyl Peroxides
-
Malonoyl peroxide 6 is an effective reagent for the syn- or anti-oxyamination of alkenes. Reaction of 6 and an alkene in the presence of O-tert-butyl-N-tosylcarbamate (R3 = CO2 tBu) leads to the anti-oxyaminated product in up to 99% yield. Use of O-methyl-N-tosyl carbamate (R3 = CO2Me) as the nitrogen nucleophile followed by treatment of the product with trifluoroacetic acid leads to the syn-oxyaminated product in up to 77% yield. Mechanisms consistent with the observed selectivities are proposed.
- Curle, Jonathan M.,Perieteanu, Marina C.,Humphreys, Philip G.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
-
supporting information
p. 1659 - 1664
(2020/02/13)
-
- Synthesis of new C3 symmetric amino acid- and aminoalcohol-containing chiral stationary phases and application to HPLC enantioseparations
-
We recently reported a new C3-symmetric (R)-phenylglycinol N-1,3,5-benzenetricarboxylic acid-derived chiral high-performance liquid chromatography (HPLC) stationary phase (CSP 1) that demonstrated better results as compared to a previously described N-3,5-dintrobenzoyl (DNB) (R)-phenylglycinol-derived CSP. Over a decade ago, (S)-leucinol, (R)-phenylglycine, and (S)-leucine derivatives were used as the starting materials of 3,5-DNB-based Pirkle-type CSPs for chiral separation. In this study, three new C3-symmetric CSPs (CSP 2, 3, and 4) were prepared by combining the ideas and results mentioned above. Here we describe the synthetic procedures and applications of the new C3-symmetric CSPs (CSP 2–CSP 4).
- Yu, Jeongjae,Armstrong, Daniel W.,Ryoo, Jae Jeong
-
-
- Catalytic, enantioselective N-acylation of lactams and thiolactams using amidine-based catalysts
-
In contrast to alcohols and amines, racemic lactams and thiolactams cannot be resolved directly via enzymatic acylation or classical resolution. Asymmetric N-acylation promoted by amidine-based catalysts, particularly Cl-PIQ 2 and BTM 3, provides a convenient method for the kinetic resolution of these valuable compounds and often achieves excellent levels of enantioselectivity in this process. Density functional theory calculations indicate that the reaction occurs via N-acylation of the lactim tautomer and that cation-π interactions play a key role in the chiral recognition of lactam substrates.
- Yang, Xing,Bumbu, Valentina D.,Liu, Peng,Li, Ximin,Jiang, Hui,Uffman, Eric W.,Guo, Lei,Zhang, Wei,Jiang, Xuntian,Houk,Birman, Vladimir B.
-
supporting information
p. 17605 - 17612
(2013/01/15)
-
- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
-
The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
- -
-
Page/Page column 45-49; 56
(2010/12/31)
-
- Resolution of pentafluorophenyl esters using oxazolidin-2-ones
-
A series of structurally related racemic pentafluorophenyl active esters were resolved using an equimolar amount of (S)-4-phenyloxazolidin-2-one. The levels of diastereocontrol were found to be excellent (80-96% de) at ~40% conversion.
- Al Shaye, Najla,Eames, Jason
-
scheme or table
p. 5892 - 5895
(2010/11/18)
-
- Development of new HPLC chiral stationary phases based on native and derivatized cyclofructans
-
An unusual class of chiral selectors, cyclofructans, is introduced for the first time as bonded chiral stationary phases. Compared to native cyclofructans (CFs), which have rather limited capabilities as chiral selectors, aliphatic-and aromatic-functionalized CF6s possess unique and very different enantiomeric selectivities. Indeed, they are shown to separate a very broad range of racemic compounds. In particular, aliphatic-derivatized CF6s with a low substitution degree baseline separate all tested chiral primary amines. It appears that partial derivatization on the CF6 molecule disrupts the molecular internal hydrogen bonding, thereby making the core of the molecule more accessible. In contrast, highly aromaticfunctionalized CF6 stationary phases lose most of the enantioselective capabilities toward primary amines, however they gain broad selectivity for most other types of analytes. This class of stationary phases also demonstrates high "loadability" and therefore has great potential for preparative separations. The variations in enantiomeric selectivity often can be correlated with distinct structural features of the selector. The separations occur predominantly in the presence of organic solvents.
- Sun, Ping,Wang, Chunlei,Breitbach, Zachary S.,Zhang, Ying,Armstrong, Daniel W.
-
experimental part
p. 10215 - 10226
(2010/05/01)
-
- Bis(o-nitrophenyl) carbonate as a new reagent for the synthesis of chiral oxazolidin-2-ones
-
Bis(o-nitrophenyl) carbonate reacts under mild conditions with chirals 1,2-amino alcohols and, after addition of DMAP, affords the corresponding oxazolidin-2-ones in very good yields.
- Simon, Monika,Micle, Andreea,Badea, Valentin,Csunderlik, Carol
-
experimental part
p. 2633 - 2639
(2010/01/06)
-
- Asymmetric synthesis of amlnocyclopropanes and N-cyclopropylamino alcohols through direct amidocyclopropanation of alkenes using chiral organozinc carbenoids
-
Chiral N-(diethoxymethyl)oxazolidinones, prepared from the corresponding oxazolidinones by heating in trielhyl orthoformate, can be used as organozinc carbenoid precursors for the direct enantioselective amidocyclopropanation of alkenes. The reaction is successful with a wide range of oxazolidinones and alkenes and proceeds with moderate to excellent yield and stereoselectivity. In most cases the trans/exo amidocyclopropane product, is favoured, although certain cyclic alkenes such as indene favour the formation of the endo cyclopropane. The products can be readily elaborated to produce cyclopropylamino alcohols and amino acids. Wiley-VCH Verlag GmbH & Co. KGaA.
- Begis, Guillaume,Cladingboel, David E.,Jerome, Laure,Motherwell, William B.,Sheppard, Tom D.
-
experimental part
p. 1532 - 1548
(2009/09/08)
-
- Synthesis and configurational assignment of the amino alcohol in the eastern fragment of the GE2270 antibiotics by regio- and stereoselective addition of 2-metalated 4-bromothiazoles to α-chiral electrophiles
-
A synthesis of the eastern fragment of the thiazole peptide GE2270 A (1) has been developed. The synthetic approach relies on the regioselective functionalization of 2,4-dibromothiazole (5) via metalation and nucleophilic addition (at C2) or palladium-mediated cross-coupling (at C2 or C4). The stereochemistry at the N-bearing stereocenter was established by coupling of 2-metalated 4-bromothiazoles (4) to enantiomerically pure mandelic acid derivatives. Both the erythro (2) and threo (3) configurated amino alcohols were prepared with high diastereoselectivities depending on the electrophile employed. More specifically, the threo-configurated (S,R)-4-bromothiazolyl β-amino alcohol 6 was synthesized from O-TBS protected (R)-mandelonitrile in 62% yield. Its N-PMB protected (R,S)-enantiomer 20 was obtained from O-TBS protected (S)-mandelic aldehyde in 67% yield. The eryrthro-configurated (S,S)-4-bromothiazolyl β-amino alcohol 29 was prepared from O-TBS protected (S)-ethyl mandelate in four steps and 33% overall yield. The bithiazole moiety in the desired products 2 and 3 was finally established by the regioselective Negishi coupling of 2,4-dibromothiazole (5) and the 4-zincated, N-Boc protected thiazole derivatives of the diastereomeric 4-bromothiazolyl β-amino alcohols 6 and 29.
- Delgado, Oscar,Heckmann, Golo,Mueller, H. Martin,Bach, Thorsten
-
p. 4599 - 4608
(2007/10/03)
-
- Kinetic resolution of 2-oxazolidinones via catalytic, enantioselective N-acylation
-
Kinetic resolution of racemic 2-oxazolidinones via catalytic, enantioselective N-acylation has been achieved for the first time and with outstanding selectivities. Copyright
- Birman, Vladimir B.,Jiang, Hui,Li, Ximin,Guo, Lei,Uffman, Eric W.
-
p. 6536 - 6537
(2007/10/03)
-
- Enantioselective acyl transfer catalysts and their use in kinetic resolution of alcohols and desymmetrization of meso-diols
-
Novel enantioselective acylation catalysts comprising chiral derivatives of DHIP and DHIQ, having the following representative general structures are disclosed: These new compounds are useful for resolving racemates or further enhancing the enantiomeric excess of an enantiomerically enriched composition and for desymmetrizing meso compounds.
- -
-
Page/Page column 20-21
(2008/06/13)
-
- Synthesis of enantiopure aminocyclopropanes by diastereoselective addition of a chiral amino substituted organozinc carbenoid to alkenes
-
The synthesis of enantiopure aminocyclopropanes is reported, via direct aminocyclopropanation of alkenes with a zinc carbenoid containing a chiral auxiliary. The methodology was applied to the synthesis of a protected aminocyclopropane present in the immu
- Begis, Guillaume,Sheppard, Tom D.,Cladingboel, David E.,Motherwell, William B.,Tocher, Derek A.
-
p. 3186 - 3188
(2007/10/03)
-
- Catalytic additions of acylsilanes to imines: An acyl anion strategy for the direct synthesis of α-amino ketones
-
(Chemical Equation Presented) The addition of acylsilanes to imines catalyzed by neutral carbenes (or zwitterions) generated in situ from readily available thiazolium salts is described. The general reaction successfully utilizes acylsilanes as carbonyl anion precursors and is tolerant of a range of structural diversity on the acylsilane or imine electrophile. The overall reaction utilizes easily available precursors and directly accesses protected α-amino ketones in the correct oxidation state.
- Mattson, Anita E.,Scheidt, Karl A.
-
p. 4363 - 4366
(2007/10/03)
-
- Asymmetric aminolysis of aromatic epoxides: A facile catalytic enantioselective synthesis of anti-β-amino alcohols
-
The first asymmetric aminolysis of trans-aromatic epoxides with anilines is described. The process affords enantioenriched anti-β-amino alcohols in up to 99% ee. The complete regio- and diastereoselectivity observed uses commercially available [Cr(Salen)CI] as a Lewis acid catalyst and in combination with a very simple experimental procedure renders the present reaction a facile and practical tool for the synthesis of chiral nonracemic anti-β-amino alcohols.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Locatelli, Manuela,Massaccesi, Massimo,Melchiorre, Paolo,Sambri, Letizia
-
p. 2173 - 2176
(2007/10/03)
-
- Carboxylation and Mitsunobu reaction of amines to give carbamates: Retention vs inversion of configuration is substituent-dependent
-
(Equation Presented) A mild method for the synthesis of carbamates from amino alcohols involves sequential carboxylation with carbon dioxide, followed by a Mitsunobu reaction. Unexpectedly, the stereochemical course of the Mitsunobu reaction is dependent on whether the carbamic acid intermediate is N-substituted with hydrogen (retention) or carbon (inversion).
- Dinsmore, Christopher J.,Mercer, Swati P.
-
p. 2885 - 2888
(2007/10/03)
-
- Chemoselective debezylation of the N-1-phenylethyl group in 2-oxazolidinones by the anisole-methanesulfonic acid system
-
The chemoselective removal of N-1-phenylethyl group in 2-oxazolidinones by the anisole-methanesulfonic acid system was investigated. Optically active 4,5-cis- and 4,5-trans-diphenyl-2-oxazolidinones (1a-d) were easily synthesized from dl-stilbene oxides (trans- and cis-7a) using this debenzylation.
- Sugiyama, Shigeo,Morishita, Kenji,Chiba, Mariko,Ishii, Keitaro
-
p. 637 - 648
(2007/10/03)
-
- Facile inversion of configuration of N-Boc-β-aminoalcohols via S(N)2 cyclization to oxazolidinones
-
Oxazolidinones are obtained by the cyclization of mesylates derived from N-Boc-β-Aminoalcohols. Hydrolysis of the N-Boc-Oxazolidinones regenerates the protected aminoalcohols with inverted configuration at the hydroxy group. (C) 2000 Elsevier Science Ltd.
- Benedetti,Norbedo
-
p. 10071 - 10074
(2007/10/03)
-
- N-carbamylamino alcohols as the precursors of oxazolidinones via nitrosation-deamination reaction
-
Oxazolidinones were effectively prepared from N-carbamylamino alcohols by treatment with nitrous acid, via N-nitroso compound as the intermediate. A new route to (R)-4-benzyloxazolidinone was developed starting from DL- phenylalanine, utilizing D-hydantoinase-catalyzed enantioselective hydrolysis of 5-benzylhydantoin under the dynamic kinetic resolution conditions, and the subsequent reduction to the precursor for the above-mentioned cyclization reaction, by taking advantage of the intermediates bearing an N-carbamylamino functionality.
- Suzuki, Masumi,Yamazaki, Takahiro,Ohta, Hiromichi,Shima, Kyoko,Ohi, Katsuhide,Nishiyama, Shigeru,Sugai, Takeshi
-
p. 189 - 192
(2007/10/03)
-
- Synthesis of chiral oxazolidin-2-ones and imidazolidin-2-ones via DMAP- catalyzed isocyanation of amines with di-tert-butyl dicarbonate
-
Oxazolidin-2-ones and imidazolidin-2-ones are prepared under mild reaction conditions by DMAP-catalyzed isocyanation of 1,2-aminoalcohols and 1,2-diamines with di-tert-butyl dicarbonate and subsequent cyclization.
- Knoelker, Hans-Joachim,Braxmeier, Tobias
-
p. 9407 - 9410
(2007/10/03)
-
- Application of erythro-2-amino-1,2-diphenylethanol as a highly efficient chiral auxiliary. highly stereoselective staudinger-type β-lactam synthesis using a 2-chloro-l-methylpyridinium salt as the dehydrating agent
-
The Staudinger-type reaction of carboxylic acids with imines, using a 2-chloro-l-methylpyridinium salt as the dehydrating reagent, proceeded smoothly under mild conditions to afford the desired β-lactams in high yields with excellent cis-selectivity. This
- Matsui, Satoshi,Hashimoto, Yukihiko,Saigo, Kazuhiko
-
p. 1161 - 1166
(2007/10/03)
-
- Diastereoselektive chelatkontrollierte Radikalcyclisierung eines chiralen, von Oxazolidinon abgeleiteten 2-Alkenamids und Modellierung des Uebergangszustands dieser Reaktion
-
Keywords: Asymmetrische Synthesen; Kraftfeldrechnungen; Oxazolidinone; Radikale; Tetraline
- Badone, Domenico,Bernassau, Jean-Marie,Cardamone, Rosanna,Guzzi, Umberto
-
p. 575 - 578
(2007/10/03)
-
- Synthetic Studies on the Key Component of the New Generation of Quinolonecarboxylic Acid, DU-6859. 2. Asymmetric Synthesis of (1R,2S)-2-Fluorocyclopropylamine
-
The title synthesis was achieved by featuring diastereoface-selective cyclopropanation of (4R,5S)-4,5-diphenyl-3-vinyl-2-oxazolidinone and its related compounds, the chiral conformationally rigid N-vinylcarbamates, with zinc-monofluorocarbenoid, followed
- Akiba, Toshifumi,Tamura, Osamu,Hashimoto, Masaru,Kobayashi, Yuko,Katoh, Tadashi,et al.
-
p. 3905 - 3914
(2007/10/02)
-
- Asymmetric Synthesis of (1R,2S)-2-Fluorocyclopropylamine, the Key Intermediate of the New Generation of Quinolonecarboxylic Acid, DU-6859
-
The title synthesis was achieved by featuring diastereoface selective cyclopropanation of (4R,5S)-4,5-diphenyl-3-vinyl-2-oxazolidinone, the chiral and conformationally rigid N-vinylcarbamate, with zincmonofluorocarbenoid followed by hydrogenolysis of form
- Tamura, Osamu,Hashimoto, Masaru,Kobayashi, Yuko,Katoh, Tadashi,Nakatani, Kazuhiko,et al.
-
p. 3487 - 3490
(2007/10/02)
-
- The Reaction of Chlorosulfonyl Isocyanate with Epoxides. A Novel Conversion of Epoxides to Cyclic Carbonates
-
The facile reaction of chlorosulfonyl isocyanate (CSI) with epoxides is described.The initially formed 2-chlorosulfonylimino-1,3-dioxolane 2a-e and N-chlorosulfonyl-1,3-oxazolidin-2-one 3a-e derivatives undergo smooth hydrolysis to yield the corresponding 1,3-dioxolan-2-one 4a-e and 1,3-oxazolidin-2-one 5a-e derivatives respectively.This reaction sequence provides a convenient one-pot method for the conversion of epoxides to cylic carbonates.Substrates such as 1g-i are exceptions to this otherwise general reaction pathway.
- Keshava Murthy, K. S.,Dhar, D. N.
-
p. 1721 - 1725
(2007/10/02)
-
- A CONVENIENT ONE-POT SYNTHESIS OF 1,3-DIOXOLAN-2-ONES FROM EPOXIDES USING CHLOROSULFONYL ISOCYANATE
-
An efficient, simple and stereospecific one-pot method is described for the conversion of epoxides to 1,3-dioxolan-2-ones, by using chlorosulfonyl isocyanate (CSI).
- Murthy, K. S. Keshava,Dhar, D. N.
-
p. 687 - 696
(2007/10/02)
-
- Improved Chiral Derivatizing Agents for the Chromatographic Resolution of Racemic Primary Amines
-
Several 4- and/or 5-aryl-substituted 2-oxazolidones have been prepared and studied as chiral derivatizing agents (CDA) for the chromatographic resolution of chiral primary amines via diastereomeric allophanates.The diastereomeric allophanates derived from either racemic primary amines and cis-4,5-diphenyl-2-oxazolidone-3-carbamyl chloride or racemic isocyanates and cis-4,5-diphenyl-2-oxazolidone show sufficient NMR chemical shift differences and chromatographic separability that this heterocyclic system should prove to be a very useful CDA for the chromatographic resolution and determination of the absolute configuration of a variety of chiral primary amines.The diastereomeric allophanates are readily hydrolyzed to return both chiral components of the allophanates in excellent yield.Both solution and adsorbed conformations of these allophanates are discussed in reference to the determination of the absolute configuration of the allophanates (and hence of the chiral primary amine) from the senses of NMR nonequivalence between and chromatographic elution order of the diastereomers.
- Pirkle, William H.,Simmons, Kirk A.
-
p. 2520 - 2527
(2007/10/02)
-