Improved Methodology for the Preparation of Chiral Amines
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Chiral Auxiliaries and Optical Resolving Agents
Chiral Auxiliaries and Optical Resolving Agents Most bioactive substances are optically active. For instance, if This brochure introduces a variety of chiral auxiliaries and a substance is synthesized as a racemic compound, its optical resolving agents. We hope that it will be useful for your enantiomer may show no activity or even undesired bioactivity. research of the synthesis of optically active compounds. Thus, methods to gain enantiopure compounds have been Additionally, TCI has some brochures introducing chiral developed. When synthesizing enantiopure compounds, the compounds for the chiral pool method in “Chiral Building Blocks”, methods are roughly divided into three methods. “Terpenes”, “Amino Acids” and other brochures. Sugar derivatives are also introduced in a catalog, “Reagents for Glyco Chemistry Chiral pool method: & Biology”, and category pages of sugar chains. Furthermore, The method using an easily available chiral compound as a TCI has many kinds of catalysts for asymmetric synthesis and starting material like an amino acid or sugar. introduce them in brochures such as “Asymmetric Synthesis” and Asymmetric synthesis: “Asymmetric Organocatalysts”, and other contents. The method to introduce an asymmetric point to compounds You can search our information through “asymmetric synthesis” without an asymmetric point. Syntheses using achiral as a keyword. auxiliaries are included here. Optical resolution: The method to separate a racemic compound into two ● Reactions with Chiral Auxiliaries enantiomers. The direct method using a chiral column and One of the most famous named reactions using chiral auxiliaries1) the indirect method to separate two enantiomers using is the Evans aldol reaction.2) This reaction is quite useful because optical resolving agents to convert into diastereomers are this reaction can efficiently introduce two asymmetric carbons into examples. -
779 Part 770—Interpretations
Pt. 770 15 CFR Ch. VII (1–1–21 Edition) in the item that qualitatively affect the per- roller bearings and parts). This applies formance of the U.S. and foreign items; to separate shipments of anti-friction (vi) Evidence of the interchangeability of bearings or bearing systems and anti- U.S. and foreign items; friction bearings or bearing systems (vii) Patent descriptions for the U.S. and foreign items; shipped with machinery or equipment (viii) Evidence that the U.S. and foreign for which they are intended to be used items meet a published industry, national, or as spares or replacement parts. international standard; (2) An anti-friction bearing or bear- (ix) A report or eyewitness account, by ing system physically incorporated in a deposition or otherwise, of the foreign item’s segment of a machine or in a complete operation; machine prior to shipment loses its (x) Evidence concerning the foreign manu- identity as a bearing. In this scenario, facturers’ corporate reputation; (xi) Comparison of the U.S. and foreign end the machine or segment of machinery item(s) made from a specific commodity, containing the bearing is the item sub- tool(s), device(s), or technical data; or ject to export control requirements. (xii) Evidence of the reputation of the for- (3) An anti-friction bearing or bear- eign item including, if possible, information ing system not incorporated in a seg- on maintenance, repair, performance, and ment of a machine prior to shipment, other pertinent factors. but shipped as a component of a com- plete unassembled (knocked-down) ma- SUPPLEMENT NO. -
Page 1 of 108 RSC Advances
RSC Advances This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. This Accepted Manuscript will be replaced by the edited, formatted and paginated article as soon as this is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/advances Page 1 of 108 RSC Advances Applications of oxazolidinones as chiral auxiliaries in the asymmetric alkylation reaction applied to total synthesis Majid M. Heravi,* Vahideh Zadsirjan, Behnaz Farajpour Department of Chemistry, School of Science, Alzahra University, Vanak, Tehran, Iran Email: [email protected] Abstract Various chiral oxazolidinones (Evans' oxazolidinones) have been employed as effective chiral auxiliaries in the asymmetric alkylation of different enolates. This strategy has been found promising and successful when used as key step (steps) in the total synthesis of several biologically active natural products. In this report, we try to underscore the applications of Manuscript oxazolidinones as chiral auxiliary in asymmetric alkylation, and particularly in crucial chiral inducing steps in the total synthesis of natural products, showing biological activities. -
Transition Metal-Catalyzed Directed C(Sp3)–H Functionalization of Saturated Heterocycles
Synthesis Review / Short Review Transition Metal-Catalyzed Directed C(sp3)–H Functionalization of Saturated Heterocycles Daniele Antermitea James A. Bull*a a Department of Chemistry, Imperial College London, White City, Wood Lane, London, W12 0BZ, United Kingdom [email protected] Click here to insert a dedication. Received: biological interactions or selectivity profiles. The ready Accepted: Published online: availability of simple saturated heterocycle derivatives, DOI: including enantioenriched derivatives, makes them ideal Abstract Synthetic methods that can readily access saturated heterocycles starting points for further reactions. Therefore, approaches to with different substitution patterns and with control of stereo- and functionalize existing C–H bonds of these readily available regiochemistry are of huge potential value in the development of new medicinal compounds. Directed C–H functionalization of simple and building blocks appears to be of considerable potential. commercially available precursors offers the potential to prepare diverse Over the last 20 years, the concept of transition metal- collections of such valuable compounds that can probe the different available exit vectors from a ring system. Nonetheless, the presence of the catalyzed C–H functionalization has emerged with enormous Lewis basic heteroatoms makes this a significant challenge. This review potential to streamline the synthesis of complex molecules.5 covers recent advances in the catalytic C–H functionalization of saturated Specifically, transition metal catalysts can activate C–H bonds heterocycles, with a view to different heterocycles (N, O, S), substitution to form discrete C–M bonds, via different mechanistic patterns and transformations. 1. Introduction pathways.6 The resulting organometallic intermediate can then 2 a-C–H Functionalization with directing group on nitrogen form new C–C or C–heteroatom bonds with various coupling 3 C–H Functionalization at unactivated C(3), C(4) and C(5) positions partners. -
Chapter 8. Chiral Catalysts José M
Chapter 8. Chiral Catalysts José M. Fraile, José I. García, José A. Mayoral 1. The Origin of Enantioselectivity in Catalytic Processes: the Nanoscale of Enantioselective Catalysis. Enantiomerically pure compounds are extremely important in fields such as medicine and pharmacy, nutrition, or materials with optical properties. Among the different methods to obtain enantiomerically pure compounds, asymmetric catalysis1 is probably the most interesting and challenging, in fact one single molecule of chiral catalyst can transfer its chiral information to thousands or even millions of new chiral molecules. Enantioselective reactions are the result of the competition between different possible diastereomeric reaction pathways, through diastereomeric transition states, when the prochiral substrate complexed to the chiral catalyst reacts with the corresponding reagent. The efficiency of the chirality transfer, measured as enantiomeric excess [% ee = (R−S)/(R+S) × 100], depends on electronic and steric factors in a very subtle form. A simple calculation shows that differences in energy of only 2 kcal/mol between these transition states are enough to obtain more than 90% ee, and small changes in any of the participants in the catalytic process can modify significantly this difference in energy. Those modifications may occur in the near environment of the catalytic centre, at less than 1 nm scale, but also at longer distances in the catalyst, substrate, reagent, solvent, or support in the case of immobilized catalysts. This is the reason because asymmetric -
APPLICATIONS in ASYMMETRIC SYNTHESIS Carlos
324 SYNTHESIS OF OCTAHYDROBENZO - 1, 2,3 - DIAZAPHOSPHOLIDINE - 2 - OXIDES AND THEIR DERIVATIVES: APPLICATIONS IN ASYMMETRIC SYNTHESIS DOI: http://dx.medra.org/ 10.17374/targets.2020.23.324 Carlos Cruz - Hernández a , José M. Landeros a , Eusebio Juaristi * a,b a Departamento de Química, Centro de Investigación y de E studios Avanzados, Avenida IPN 2508, 07360 Ciudad de México, Mexico b El Colegio Nacional, Luis González Obregón 23, Centro Histórico, 06020 Ciudad de México, Mexico (e - mail: [email protected]; [email protected]) Abstract. This chapter outlines recent efforts devoted to the synthesis of heterocycles that include the octahydrobenzo - 1,3,2 - diazaphospholidine - 2 - oxide fragment, as well as their application in asymmetri c synthesis. The first part of this review provides a brief discussion of the general structural characteristics of this phosphorus - containing heterocyclic scaffold. The second part describes the synthetic paths that were undertaken to synthesize the desir ed heterocycles , as well as some relevant considerations pertaining the spectroscopic characterization of the phosphorus - containing heterocycles of interest . The third part provides several illustrative examples where the novel chiral heterocycles were employed in ena ntioselective synthesis. The new phosphorus - containing heterocycles proved useful : i) as chiral auxiliaries in nucleophilic addition reactions, as well as as imine activators in electrophilic addition reactions; ii ) as c hiral ligands i n nucleophilic allylation and crotonylation of prochiral aldehydes , and iii) as c hiral organocatalysts in enantioselective aldol, Michael, and cascade reactions. Contents 1. Introduction 2. Synthesis of the octahydrobenzo - 1,3,2 - diazaphospho lidine - 2 - oxide s 2.1 . Conformational and configurational assignments 3 . -
Application of Chiral Sulfoxides in Asymmetric Synthesis
MOJ Bioorganic & Organic Chemistry Review Article Open Access Application of chiral sulfoxides in asymmetric synthesis Abstract Volume 2 Issue 2 - 2018 Chiral sulfoxides are used as a toolbox for the synthesis of enantiomeric/diastereomeric compounds, which are used as precursors for the pharmaceutically/chemically Ganapathy Subramanian Sankaran,1 important molecules. The current review focuses on applying these chiral sulfoxides Srinivasan Arumugan,2 Sivaraman towards the synthesis of the compounds having stereogenic center. In general, the 3 stereogenic center induced by the sulfoxide is able to direct the stereochemistry of Balasubramaniam 1University of Massachusetts Medical School, USA further transformation necessary to complete the total synthesis of bioactive molecules. 2Department of Science and Humanity (Chemistry), Karunya The nature of the reactive conformation of the sulfoxide is strongly dependent on the Institute of Technology and Sciences, India nature of the substituents at C-α and/or C-β. 3Indian Institute of Technology Madras, Chennai, India Correspondence: Sivaraman Balasubramaniam, Senior Research Scientist, Indian Institute of Technology Madras, Chennai, India, Tel +9177 1880 5113, Email [email protected] Received: March 07, 2018 | Published: March 29, 2018 Introduction occurred in a further oxidation step of one of the sulfinyl enantiomer to sulfone.13 The titanium-binaphthol complex catalyzes not only the Over the last three decades, the sulfinyl group has received asymmetric oxidation but also the kinetic -
Asymmetric Synthesis
Chapter 45 — Asymmetric synthesis - Pure enantiomers from Nature: the chiral pool and chiral induction - Asymmetric synthesis: chiral auxiliaries Enolate alkylation Aldol reaction - Enantiomeric excess (ee) - Asymmetric synthesis: chiral reagents and catalysts CBS reagent for chiral reductions Sharpless asymmetric epoxidation Synthesizing pure enantiomers starting from Nature’s chiral pool AcO OH HO B O O HO – O O HO + O N OH H3N OH HO OH O H … AcO HO OH O OH Sulcatol - insect pheremone HO Synthesis from the chiral pool — chiral induction turns one stereocenter into many 40 steps Me HO H Me H O O OH O O OBn O * * Only one H O HO chiral reagent H H Me OBn Me Deoxyribose Fragment of Brevetoxin B Asymmetric synthesis 1. Producing a new stereogenic centre on an achiral molecule makes two enantiomeric transition states of equal energy… and therefore two enantiomeric products in equal amounts. O O 1 1 Nu R R2 R R2 Nu E OH OH 1 O 1 Nu R R Nu R2 R2 1 R R2 O Ph OH HO Ph PhLi + N N N Asymmetric synthesis 2. O 1 R R* Nu When there is an existing O chiral centre, the two possible TS’s are diastereomeric and E 1 Nu R R* can be of different energy. Thus one isomer of the new stereogenic centre can be OH O OH produced in a larger amount. 1 1 R Nu Nu R *R 1 R* R R* HO Ph O O O Ph OH PhLi PhLi Ph Ph N N N N N Ph N N N N N OH Ph O O O Ph OH Ph A removable chiral centre… synthesis with chiral auxiliaries O ??? O R R 1) Add a chiral 3) Remove the auxiliary chiral auxiliary O O R* R* 2) Add the new stereocentre via chiral induction Enantiopure oxazolidinones as chiral auxiliaries 1. -
A Sustainable, Two-Enzyme, One-Pot Procedure
A Sustainable, Two-Enzyme, One-Pot Procedure for the Synthesis of Enantiomerically Pure α-Hydroxy Acids Andrzej Chmura Cover picture: Manihot esculenta (cassava), source: http://www.hear.org/starr/images/image/?q=090618-1234&o=plants SEM photograph of an Me HnL CLEA (author: Dr. Rob Schoevaart, CLEA Technologies, Delft, The Netherlands) Cover design by Andrzej Chmura A Sustainable, Two-Enzyme, One-Pot Procedure for the Synthesis of Enantiomerically Pure α-Hydroxy Acids PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof.ir. K.C.A.M. Luyben, voorzitter van het College voor Promoties, in het openbaar te verdedigen op dinsdag 7 december 2010 om 12.30 uur door Andrzej CHMURA Magister inŜynier in Chemical Technology, Politechnika Wrocławska, Wrocław, Polen en Ingenieur in Chemistry, Hogeschool Zeeland, Vlissingen, Nederland geboren te Łańcut, Polen Dit proefschrift is goedgekeurd door de promotor: Prof. dr. R.A. Sheldon Copromotor: Dr. ir. F. van Rantwijk Samenstelling promotiecommissie: Rector Magnificus Voorzitter Prof. dr. R.A. Sheldon Technische Universiteit Delft, promotor Dr. ir. F. van Rantwijk Technische Universiteit Delft, copromotor Prof. dr. I.W.C.E. Arends Technische Universiteit Delft Prof. dr. W.R. Hagen Technische Universiteit Delft em. Prof. dr. A.P.G. Kieboom Universiteit Leiden Prof. dr. A. Stolz Universität Stuttgart Prof. dr. V. Švedas Lomonosov Moscow State University Prof. dr. J.J. Heijnen Technische Universiteit Delft, reserve lid The research described in this thesis was financially supported by The Netherlands Research Council NWO under the CERC3 programme and by COST action D25. ISBN/EAN: 978-90-9025856-0 Copyright © 2010 by Andrzej Chmura All rights reserved. -
Stereoselective Synthesis of Chiral
S S symmetry Article Stereoselective Synthesis of Chiral α-SCF3-β-Ketoesters FeaturingArticle a Quaternary Stereocenter Stereoselective Synthesis of Chiral α-SCF3-β-Ketoesters Monica Fiorenza Boselli, Chiara Faverio, Elisabetta Massolo, Laura Raimondi, Alessandra Puglisi andFeaturing Maurizio Benaglia a Quaternary * Stereocenter Monica Fiorenza Boselli, ChiaraDipartimento Faverio, diElisabetta Chimica, UniversitMassolo,à Lauradegli Studi Raimondi, di Milano, Alessandra Via Golgi 19,Puglisi I-20133 and Milano, Maurizio Italy; Benaglia * monicafi[email protected] (M.F.B.); [email protected] (C.F.); [email protected] (E.M.); [email protected] (L.R.); [email protected] (A.P.) *DipartimentoCorrespondence: di Chimica, [email protected]; Università degli Studi di Milano, Tel.: Via +39-02-5031-4171; Golgi 19, I-20133 Milano, Fax: +39-02-5031-4159 Italy; [email protected] (M.F.B.); [email protected] (C.F.); [email protected] (E.M.); Abstract:[email protected] development (L.R.); of [email protected] new and efficient methods, (A.P.) reagents, and catalysts for the introduction * Correspondence: [email protected]; Tel.: +39-02-5031-4171; Fax: +39-02-5031-4159 of fluorine atoms or fluorinated moieties in molecular scaffolds has become a topic of paramount importanceAbstract: The in development organic synthesis. of new and In thisefficient framework, methods, thereagents, incorporation and catalysts of thefor SCFthe introduc-3 group into organic moleculetion of fluorine has oftenatoms ledor fluorinated to beneficial moieties effects in molecular on the drug’s scaffolds metabolic has become stability a topic andof para- bioavailability. Heremount we importance report ourin organic studies synthesis. -
Ketoreductases Ketoreduktasen Céto-Réductases
(19) TZZ¥_¥__T (11) EP 3 134 519 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C12N 9/04 (2006.01) 06.06.2018 Bulletin 2018/23 (86) International application number: (21) Application number: 15717166.1 PCT/EP2015/058411 (22) Date of filing: 17.04.2015 (87) International publication number: WO 2015/162064 (29.10.2015 Gazette 2015/43) (54) KETOREDUCTASES KETOREDUKTASEN CÉTO-RÉDUCTASES (84) Designated Contracting States: • PETRI, Andreas AL AT BE BG CH CY CZ DE DK EE ES FI FR GB 04155 Leipzig (DE) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO • SCHWARZE, Daniel PL PT RO RS SE SI SK SM TR 07749 Jena (DE) • STRUHALLA, Marc (30) Priority: 22.04.2014 EP 14165444 04229 Leipzig (DE) • GREINER-STÖFFELE, Thomas (43) Date of publication of application: 99610 Sömmerda (DE) 01.03.2017 Bulletin 2017/09 (74) Representative: Kutzenberger Wolff & Partner (73) Proprietor: c-LEcta GmbH Theodor-Heuss-Ring 23 04103 Leipzig (DE) 50668 Köln (DE) (72) Inventors: (56) References cited: • SCHMIEDEL, Ramona EP-A1- 1 553 170 04277 Leipzig (DE) • VOGEL, Andreas • DATABASE PROTEIN [Online] 22 October 2013 04105 Leipzig (DE) (2013-10-22), "Short-chain dehydrogenase • KÖPKE, Sabrina [Glaciibacter superstes]", XP002731083, 04315 Leipzig (DE) retrieved from NCBI Database accession no. •CZAJA,Rico WP_022887115 04155 Leipzig (DE) • FELLER, Claudia Remarks: 04155 Leipzig (DE) Thefile contains technical information submitted after • MERKENS, Hedda the application was filed and not included in this 22395 Hamburg (DE) specification • RZEZNICKA, Kamila 04105 Leipzig (DE) Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. -
Synthesis and Polymerizability of Atom-Bridged Bicyclic Monomers
Polymers 2012, 4, 1674-1686; doi:10.3390/polym4041674 OPEN ACCESS polymers ISSN 2073-4360 www.mdpi.com/journal/polymers Review Synthesis and Polymerizability of Atom-Bridged Bicyclic Monomers Henry K. Hall, Jr. Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ 85721, USA; E-Mail: [email protected]; Tel.: +1-520-621-6326; Fax: +1-520-621-8407 Received: 11 September 2012; in revised form: 19 November 2012 / Accepted: 20 November 2012 / Published: 5 December 2012 Abstract: The synthesis and polymerizability of atom-bridged bicyclic monomers was surveyed. The monomers included lactams, ureas, urethanes, lactones, carbonates, ethers, acetals, orthoesters, and amines. Despite widely-varying structures, they almost all polymerized to give polymers with monocyclic rings in the chain. The polymerizations are grouped by mechanism: uncoordinated anionic, coordinated anionic, and cationic. Keywords: alicyclic ring-containing polymers; anti-Bredt monomers; atom-bridged bicyclic monomers; ring-opening polymerizations 1. Introduction Ring-opening polymerizations, which convert cyclic monomers into linear polymers, are a major type of polymerization. A recent authoritative treatise [1] covered ring-opening polymerization of monocyclic monomers; this Review covers ring-opening polymerization of atom-bridged bicyclic monomers. “Atom-bridged” means all three chains connecting the bridgehead atoms contain at least one atom. Bicyclic compounds with bridgehead atoms directly attached to one another will not be considered here because they usually polymerize like monocyclics. Alkene metathesis of bicyclic monomers has been well-reviewed elsewhere and will not be included here. The reactions are arranged below according to mechanism: UNCOORDINATED ANIONIC POLYMERIZATIONS of lactams, ureas, and urethanes COORDINATED ANIONIC POLYMERIZATIONS of lactones and carbonates CATIONIC POLYMERIZATIONS of ethers, acetals, orthoesters and amines Polymers 2012, 4 1675 Although these monomers may appear exotic, they are often synthesized rather easily.