DOCSLIB.ORG

Functional Group Reactions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Functional Group Reactions 14C synthesis strategies, Chem 315/316 / Beauchamp 1 Functional Group Reactions O O Alkanes: Make O from R Br OH R Br R H R R R H haloalkanes S H haloalkanes aldehydes aldehydes alkenes alkynes O H2SO4 1. LiAlH4 & ketones & ketones H2O 1. Mg (LiAlD4) Wolff-Kishner Clemmenson H2 /Pd H2 /Pd 2. workup 2. workup NH2NH2 /ROH/ Zn / HCl aromatic sulfonic acids y:\files\classes\316\special handouts\316_FG_syn.doc 14C synthesis strategies, Chem 315/316 / Beauchamp 2 O Esters O O O O O O Make R OH ROH R OH R R' from R O R OH R Cl ketones R' H2SO4 (-H2O) RBr RBr alkene R O ROH mCPBA Fischer ester syn Baeyer-Villigar S 2 S 1 N N acyl substitution acyl substitution H2SO4 rxn O Aldehydes O OH N R R O C Make R R O R Cl R R from R nitriles esters acid chlorides 1o alcohols alkenes alkynes 1. HCON(CH ) /POCl R H 1. R AlH 3 2 3 CrO 1. R2AlH 1. R2AlH 2 2. workup 3 1. O , -78oC 1. R BH pyridine 3 2 (DIBAH) (DIBAH) (DIBAH) 2. H O , HO Vilsmeier Rxn (PCC) 2. CH3SCH3 2 2 2. workup 2. workup 2. workup Ketones R O O O OH N R O O O C Make R' R R NR R 2 R' Cl R R' R OH from R R' 3o amides 2o alcohols R' alkynes nitriles acid chlorides ketals acids R R' CrO3 alkenes deprotect 1. 2 eqs. R'Li H2SO4/H2O 1. R'MgBr 1. R'MgBr 1. R2Cu Li 2. workup pyridine o 1. O , -78 C +2 2. workup 2. workup 2. workup + (PCC) 3 Hg cat. H O /H O (2 ways) (2 ways) (2 ways) 3 2 2. CH3SCH3 (2 ways) O O O 1o, 2o, 3o amides N C O Make from R' Cl R' O R R R acid chlorides anhydrides nitriles R N o from from (1 amides) NH , 1o, 2o amides o o R = C, H R 3 NH3, 1 , 2 amides HCl / H2O O Reactions of Acid Chlorides O R' O O O O R N R O O O R" aromatic R' R H R R R O R' 1o,2o,3o amides R' ketones R Cl R O anhydrides esters R S aldehydes ketones H thioesters R R AlCl O Cu 3 O N Al H SH R Li R' H R' R Friedel-Crafts R' cuprates R' OH R=CorH R DIBAH Acylation y:\files\classes\316\special handouts\316_FG_syn.doc 14C synthesis strategies, Chem 315/316 / Beauchamp 3 Reactions of Alkenes OH OH Br Br OH OH Br Br Br + HBr / ROOR H3O / H2O 1. Hg(OAc)2/H2O 1. BH3 2. NaBH or (poss. rearrangement) 4 2. H2O2 / HO HBr Br2 Br2 / H2O (no rearrangement) (anit-Markovnikov) 1. BH3 OH 2. Br2 / CH3O (anit-Markovnikov) NaOH OH (mild) O O OH O OH O HO O OH OH CH 2 CH3 C O + OsO or KMnO H / Pd o o H H O / H O 4 4 2 1. O3 , -78 C 1. O , -78 C o OH 2 2 mCPBA syn diol 3 1. O3 , -78 C or 2. CH3SCH3 2. NaBH4 2. H O , HO 2 2 anti diol H2O / HO Alkynes H R Br Br R electrophiles H H R R X O Make R R R alkynes haloalkanes from alkene alkynes R R dihaloalkane 1. NaNR 1. Br 2 O 2 1. NaNR 1. NaNR2 2. NaNR 2 excess/zipper aldehydes excess/zipper excess/zipper excess/zipper 2. electrophile & ketones R 2. workup 2. workup 3. workup 3. workup epoxides Reactions of Alkynes OH O O Br OH H 1. R BH + 2 H3O / H2O 2. H O HO +2 2 2 / 1. NaNR2 1. NaNR Hg cat. (anit-Markovnikov) HBr 2 1. NaNR2 2. 2. O 2. Br O H 3. workup 3. workup Reactions of Alkynes O start O over H Pd, H2 1. excess NaNR 1. R BH Na / NH / ROH Pd, H 2 2 quinoline 3 2 2. workup 2. H O HO H O+ / H O E alkenes 2 2 / 3 2 (Lindlar's Cat.) (zipper reaction) (anit-Markovnikov) Hg+2 cat. Z alkenes O R R R H O aldehydes & ketones Make from alkene alkene H3C H3C R epoxides S CH n-butyl lithium 1. Br2 /H2O 2 S CH3 mCPBA 2. mild NaOH H3C sulfur ylid H3C I anhydrides acid chlorides & acids O O O O Make from R O R' R Cl R' OH (2 ways) Organometallics (Li, Mg, Cu) 2 eqs. Make R X Make R X R Cu R Make from from R Li R Li from haloalkanes R (MgBr) haloalkanes Li CuBr Li Mg y:\files\classes\316\special handouts\316_FG_syn.doc 14C synthesis strategies, Chem 315/316 / Beauchamp 4 Mg and Li Organometallics Reactions OH OH OH OH O O OH R Li R R" R R' R R R R' R' R' R OH R R' R (MgBr) O O O O O N O similar C C R chemistry O R' H H R' H R' R" R' O 1. make R-Metal 1. make R-Metal 1. make R-Metal 1. make R-Metal 1. make R-Metal 1. make R-Metal 1. make R-Metal 2. electrophile 2. electrophile 2. electrophile 2. electrophile 2. electrophile 2. electrophile 2. electrophile 3. workup 3. workup 3. workup 3. workup 3. workup 3. workup 3. workup Mg and Li Organometallics Reactions OH O OH OH R Li R R R" R' R R R' R' R R R' O (MgBr) O similar O O R' R" chemistry R' NR R' Cl 2 R' 1. make R-Metal 1. make R-Metal 1. make R-Metal 1. make R-Metal o 2. electrophile 2. electrophile 2. electrophile 2. 3 amides 3. workup 3. workup 3. workup 3. workup Cuprate Reactions Li Li Li R Cu R R Cu R O R Cu R R O Make Make Make O from from O R R' R' X from R R' (2 ways) haloalkanes (2 ways) R' Cl conjugate addition Dithiane Synthesis of Aldehydes and Ketones S R S S S S O O R Make R Make from R' Li from S S S S S R R' R H 1. n-BuLi HgBr HgBr2 Aldehydes 2 Br n-BuLi Ketones H2O 2. R'Br H2O R OH S Dithiane Synthesis S S S OH O Make S Li S S HO from S O OH 1. 2 eqs. n-BuLi 1. HgBr OH 2. H C=O 2 2 n-BuLi H O 3. workup 2. workup 2 Wittig Reactions Ph R Ph O Ph Ph Make P Ph Ph R' from P makes very C specific alkenes HC n-butyl lithium P R Br R H H2C Br Ph Ph (usually Z) R (very strong base) R carbonyl Ph (2 ways) compound ylid (Wittig salt) Enolate Chemistry electrophiles O O O R X E haloalkanes o 1. LDA,-78 C aldehydes or 2. electrophile (E) O (aldol rxns) 3. workup O O & ketones epoxides (Claisen rxns) R R E O O y:\files\classes\316\special handouts\316_FG_syn.doc 14C synthesis strategies, Chem 315/316 / Beauchamp 5 Acetoacetic Ester Synthesis + O H3O /H2O/ O 1. RO Na O O O or 2. electrophile (E) R HO /H O/ R 3. workup O 2 O O E (-CO2) E O R X substituted acetones electrophiles haloalkanes epoxides aldehydes & ketones y:\files\classes\316\special handouts\316_FG_syn.doc 14C synthesis strategies, Chem 315/316 / Beauchamp 6 O O Electrophilic Aromatic Substitution Reactions (aromatic ring is a nucleophile) 1. CO 2 NaOH, second substituent 2. WK OH RX OR Reaction 1 1 o/p dibromo Br2 Br 2 o/p bromo / alkyl FeBr3 1. H2CO 3 o/p bromo / keto 2. WK OH HBr Br ortho/para director 4 o/p bromo / nitro Organometallic O 5 o/p bromo / sulfonic acid reactions 1. C R R H Reaction 2 1 o/p alkyl / bromo (MgBr) NaCN R 2. WK OH RCl 2 o/p alkyl / alkyl AlCl Br 3 Mg O 3 o/p alkyl / keto CN 1. alkyl benzenes 4 o/p alkyl / nitro C RR ortho/para director R R O 5 o/p alkyl / sulfonic acid the aromatic ring 2. WK is a nuclephile, OH O 1 meta keto / bromo Reaction 3 the electron donation O Cl R poor reaction R 2 comes from an sp2 AlCl3 1. C 1. amine (1.LAH, 2. WK) 3 poor reaction orbital not the R OR' 2. amide (HCl, H O) 4 meta keto / nitro electrons 2. WK 2 aromatic ketones R 3. acid (H SO , H O) meta director 5 meta keto / sulfonic acid reacts 2 4 2 4. ketone (1.RMgBr, 2. WK) twice OH Reaction 4 1 meta nitro / bromo 5. aldehyde (1.DIBAH, 2. WK) HNO3 NO O 2 2 1. H2SO4 poor reaction HBr OH OH Ph 3 poor reaction 2. WK CrO 4 meta dinitro 3 O meta director (PCC) Ph 5 meta nitro / sulfonic acid 1. O CrO3 H Reaction 5 meta director 1 meta sulfonic acid / bromo OH R H2O H SO SO3H 2 poor reaction 2. WK O 2 4 (Jones) Ph 3 poor reaction R OH benzene sulfonic acids and this reaction 4 meta sulfonic acid / nitro 1. CuBr R CrO can be reversed with the addition of water. meta disulfonic acid 2. RX 3 5 (PCC) O the aromatic ring Cl CuCl 1.
Load more

Recommended publications
  • Direct Β‑Functionalization of Cyclic Ketones with Aryl Ketones Via the Merger of Photoredox and Organocatalysis Filip R
    Communication pubs.acs.org/JACS Direct β‑Functionalization of Cyclic Ketones with Aryl Ketones via the Merger of Photoredox and Organocatalysis Filip R. Petronijevic,́† Manuel Nappi,† and David W. C. MacMillan* Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States *S Supporting Information ABSTRACT: The direct β-coupling of cyclic ketones with aryl ketones has been achieved via the synergistic combination of photoredox catalysis and organocatalysis. Diaryl oxymethyl or aryl−alkyl oxymethyl radicals, transiently generated via single-electron reduction of ketone precursors, readily merge with β-enaminyl radical species, generated by photon-induced enamine oxidation, to produce γ-hydroxyketone adducts. Experimental evidence indicates that two discrete reaction pathways can be operable in this process depending upon the nature of the ketyl radical precursor and the photocatalyst. he direct β-functionalization of saturated ketones and T aldehydes is an important yet elusive goal in organic chemistry.1 While carbonyl groups are readily amenable to ipso- and α-carbon substitution with a range of nucleophiles and electrophiles respectively,2,3 activation at the β-methylene position poses a significant synthetic challenge. With a few notable exceptions,1,4 carbonyl β-functionalization has tradition- ally been restricted to the conjugate addition of soft nucleophiles are accessed via carbene catalysis,9,10 nucleophilic addition of into α,β-unsaturated carbonyl systems. As such, the development acetal-protected Grignard reagents,11 or stoichiometric metal- 5 − of a general catalytic platform for the direct β-functionalization activated homoenolate equivalents.12 16 of saturated ketones or aldehydes would represent a conceptual Drawing from the mechanistic insights gained in the course of and practical advance for the field.
    [Show full text]
  • United States Patent Office
    Patented Mar. 30, 1948 2,438,754 UNITED STATES PATENT OFFICE 2,438,754 COPPER, CONTAINING DSAZO, DYESTUFFS Adolf Krebser, Riehen, near Basel, and Werner Bossard, Basel, Switzerland, assignors to the firm J. R. Geigy A. G., Basel, Switzerland No Drawing. Application March 1, 1943, Serial : No. 477,630. In Switzerland April 28, 1942 1. Claims. (C. 260-148) 2 - It has been found that valuable new Copper For the dyestuffs of the type (a): 2-amino containing disazo dyestuffs are obtained by 1-hydroxy-, -methoxy- or -benzyloxybenzene coupling a diazotised amino Sulfonic acid of the 4-Sulfonic acid, 4- or 6-methyl-2-amino-1-hy benzene or naphthalene series, which contains, in droxy- or ethoxybenzene sulfonic acid, 4- or o-position to the amino group, a hydroxy group 5 6-chloro-2-amino-1-hydroxy- or -methoxyben or a Substituent convertible into a hydroxy group Zene Sulfonic acid, 4- or 6-nitro-2-amino-1-hy. by coppering, with a 1:3-dihydroxy-benzene, droxy- or -methoxybenzene sulfonic acid, then causing a diazonium compound which is 1-amino-2-hydroxynaphthalene-4-sulfonic acid, free from sulfonic acid groups to react with the 6-nitro-2-amino-1-hydroxynaphthalene - 4 -sul said monoazo dyestuff and after-treating the 0. fonic acid. so-obtained disazo dyestuff with copper-yielding For the dyestuffs of the type (b) and (c) : agents, with the condition that at least one of 3-amino-4-hydroxy-, -methoxy- or -chloro-1:1'- the diazo components is substituted by a phenyl diphenylsulfone-5- or -3'-sulfonic acid, 3-amino nucleus bound by a non-basic bridge.
    [Show full text]
  • Cofactor Binding Protects Flavodoxin Against Oxidative Stress
    Cofactor Binding Protects Flavodoxin against Oxidative Stress Simon Lindhoud1., Willy A. M. van den Berg1., Robert H. H. van den Heuvel2¤, Albert J. R. Heck2, Carlo P. M. van Mierlo1, Willem J. H. van Berkel1* 1 Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands, 2 Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands Abstract In organisms, various protective mechanisms against oxidative damaging of proteins exist. Here, we show that cofactor binding is among these mechanisms, because flavin mononucleotide (FMN) protects Azotobacter vinelandii flavodoxin against hydrogen peroxide-induced oxidation. We identify an oxidation sensitive cysteine residue in a functionally important loop close to the cofactor, i.e., Cys69. Oxidative stress causes dimerization of apoflavodoxin (i.e., flavodoxin without cofactor), and leads to consecutive formation of sulfinate and sulfonate states of Cys69. Use of 7-chloro-4- nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) reveals that Cys69 modification to a sulfenic acid is a transient intermediate during oxidation. Dithiothreitol converts sulfenic acid and disulfide into thiols, whereas the sulfinate and sulfonate forms of Cys69 are irreversible with respect to this reagent. A variable fraction of Cys69 in freshly isolated flavodoxin is in the sulfenic acid state, but neither oxidation to sulfinic and sulfonic acid nor formation of intermolecular disulfides is observed under oxidising conditions. Furthermore, flavodoxin does not react appreciably with NBD-Cl. Besides its primary role as redox- active moiety, binding of flavin leads to considerably improved stability against protein unfolding and to strong protection against irreversible oxidation and other covalent thiol modifications.
    [Show full text]
  • Organic Chemistry
    Wisebridge Learning Systems Organic Chemistry Reaction Mechanisms Pocket-Book WLS www.wisebridgelearning.com © 2006 J S Wetzel LEARNING STRATEGIES CONTENTS ● The key to building intuition is to develop the habit ALKANES of asking how each particular mechanism reflects Thermal Cracking - Pyrolysis . 1 general principles. Look for the concepts behind Combustion . 1 the chemistry to make organic chemistry more co- Free Radical Halogenation. 2 herent and rewarding. ALKENES Electrophilic Addition of HX to Alkenes . 3 ● Acid Catalyzed Hydration of Alkenes . 4 Exothermic reactions tend to follow pathways Electrophilic Addition of Halogens to Alkenes . 5 where like charges can separate or where un- Halohydrin Formation . 6 like charges can come together. When reading Free Radical Addition of HX to Alkenes . 7 organic chemistry mechanisms, keep the elec- Catalytic Hydrogenation of Alkenes. 8 tronegativities of the elements and their valence Oxidation of Alkenes to Vicinal Diols. 9 electron configurations always in your mind. Try Oxidative Cleavage of Alkenes . 10 to nterpret electron movement in terms of energy Ozonolysis of Alkenes . 10 Allylic Halogenation . 11 to make the reactions easier to understand and Oxymercuration-Demercuration . 13 remember. Hydroboration of Alkenes . 14 ALKYNES ● For MCAT preparation, pay special attention to Electrophilic Addition of HX to Alkynes . 15 Hydration of Alkynes. 15 reactions where the product hinges on regio- Free Radical Addition of HX to Alkynes . 16 and stereo-selectivity and reactions involving Electrophilic Halogenation of Alkynes. 16 resonant intermediates, which are special favor- Hydroboration of Alkynes . 17 ites of the test-writers. Catalytic Hydrogenation of Alkynes. 17 Reduction of Alkynes with Alkali Metal/Ammonia . 18 Formation and Use of Acetylide Anion Nucleophiles .
    [Show full text]
  • Aldehydes and Ketones
    12 Aldehydes and Ketones Ethanol from alcoholic beverages is first metabolized to acetaldehyde before being broken down further in the body. The reactivity of the carbonyl group of acetaldehyde allows it to bind to proteins in the body, the products of which lead to tissue damage and organ disease. Inset: A model of acetaldehyde. (Novastock/ Stock Connection/Glow Images) KEY QUESTIONS 12.1 What Are Aldehydes and Ketones? 12.8 What Is Keto–Enol Tautomerism? 12.2 How Are Aldehydes and Ketones Named? 12.9 How Are Aldehydes and Ketones Oxidized? 12.3 What Are the Physical Properties of Aldehydes 12.10 How Are Aldehydes and Ketones Reduced? and Ketones? 12.4 What Is the Most Common Reaction Theme of HOW TO Aldehydes and Ketones? 12.1 How to Predict the Product of a Grignard Reaction 12.5 What Are Grignard Reagents, and How Do They 12.2 How to Determine the Reactants Used to React with Aldehydes and Ketones? Synthesize a Hemiacetal or Acetal 12.6 What Are Hemiacetals and Acetals? 12.7 How Do Aldehydes and Ketones React with CHEMICAL CONNECTIONS Ammonia and Amines? 12A A Green Synthesis of Adipic Acid IN THIS AND several of the following chapters, we study the physical and chemical properties of compounds containing the carbonyl group, C O. Because this group is the functional group of aldehydes, ketones, and carboxylic acids and their derivatives, it is one of the most important functional groups in organic chemistry and in the chemistry of biological systems. The chemical properties of the carbonyl group are straightforward, and an understanding of its characteristic reaction themes leads very quickly to an understanding of a wide variety of organic reactions.
    [Show full text]
  • Aldehydes and Ketones Are Simple Organic Compounds Containing a Carbonyl Group
    Aldehydes and Ketones are simple organic compounds containing a carbonyl group. Carbonyl group contains carbon- oxygen double bond. These organic compounds are simple because the carbon atom presents in the carbonyl group lack reactive groups such as OH or Cl. By Dr. Sayed Hasan Mehdi Assistant Professor Department of Chemistry Shia P.G. College, Lucknow Dr. S.Hasan Mehdi 6/13/2020 This is to bring to kind notice that the matter of this e- content is for the B.Sc. IV semester students. It has been taken from the following sources. The students are advised to follow these books as well. •A TEXTBOOK OF ORGANIC CHEMISTRY by Arun Bahl & B.S. Bahl, S. Chand & Company Ltd. Publication. •Graduate Organic Chemistry by M. K. Jain and S.C. Sharma, Vishal Publishing Co. •Pradeep’s Organic Chemistry Vol II by R. N. Dhawan, Pradeep Publication, Jalandhar. Dr. S.Hasan Mehdi 6/13/2020 An aldehyde is one of the classes of carbonyl group- containing alkyl group on one end and hydrogen on the other end. The R and Ar denote alkyl or aryl member respectively. In the condensed form, the aldehyde is written as –CHO. Dr. S.Hasan Mehdi 6/13/2020 Dr. S.Hasan Mehdi 6/13/2020 1. From Alcohols: a. By oxidation of Alcohols: Aldehydes and ketones can be prepared by the controlled oxidation of primary and secondary alcohols using an acidified solution of potassium dichromate or permanganate. Primary alcohol produces aldehydesRef. Last slide. O K Cr O RCH2OH + [O] 2 2 7 + R C H H 10 Alcohol Aldehyde O CH3CH2OH+ [O] K2Cr2O7 + CH3 C H H Ethyl Alcohol Acetaldehyde The aldehydes formed in the above reaction are very easily oxidised to carboxylc acids if allowed to remain in the reaction mixture.
    [Show full text]
  • Recent Advances in Titanium Radical Redox Catalysis
    JOCSynopsis Cite This: J. Org. Chem. 2019, 84, 14369−14380 pubs.acs.org/joc Recent Advances in Titanium Radical Redox Catalysis Terry McCallum, Xiangyu Wu, and Song Lin* Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States ABSTRACT: New catalytic strategies that leverage single-electron redox events have provided chemists with useful tools for solving synthetic problems. In this context, Ti offers opportunities that are complementary to late transition metals for reaction discovery. Following foundational work on epoxide reductive functionalization, recent methodological advances have significantly expanded the repertoire of Ti radical chemistry. This Synopsis summarizes recent developments in the burgeoning area of Ti radical catalysis with a focus on innovative catalytic strategies such as radical redox-relay and dual catalysis. 1. INTRODUCTION a green chemistry perspective, the abundance and low toxicity of Ti make its complexes highly attractive as reagents and Radical-based chemistry has long been a cornerstone of 5 1 catalysts in organic synthesis. synthetic organic chemistry. The high reactivity of organic IV/III radicals has made possible myriad new reactions that cannot be A classic example of Ti -mediated reactivity is the reductive ring opening of epoxides. This process preferentially readily achieved using two-electron chemistry. However, the − high reactivity of organic radicals is a double-edged sword, as cleaves and functionalizes the more substituted C O bond, the selectivity of these fleeting intermediates can be difficult to providing complementary regioselectivity to Lewis acid control in the presence of multiple chemotypes. In addition, promoted epoxide reactions. The synthetic value of Ti redox catalysis has been highlighted by their many uses in total catalyst-controlled regio- and stereoselective reactions involv- 6−10 ing free-radical intermediates remain limited,2 and the synthesis (Scheme 1).
    [Show full text]
  • Chapter 14 – Aldehydes and Ketones
    Chapter 14 – Aldehydes and Ketones 14.1 Structures and Physical Properties of Aldehydes and Ketones Ketones and aldehydes are related in that they each possess a C=O (carbonyl) group. They differ in that the carbonyl carbon in ketones is bound to two carbon atoms (RCOR’), while that in aldehydes is bound to at least one hydrogen (H2CO and RCHO). Thus aldehydes always place the carbonyl group on a terminal (end) carbon, while the carbonyl group in ketones is always internal. Some common examples include (common name in parentheses): O O H HH methanal (formaldehyde) trans-3-phenyl-2-propenal (cinnamaldehyde) preservative oil of cinnamon O O propanone (acetone) 3-methylcyclopentadecanone (muscone) nail polish remover a component of one type of musk oil Simple aldehydes (e.g. formaldehyde) typically have an unpleasant, irritating odor. Aldehydes adjacent to a string of double bonds (e.g. 3-phenyl-2-propenal) frequently have pleasant odors. Other examples include the primary flavoring agents in oil of bitter almond (Ph- CHO) and vanilla (C6H3(OH)(OCH3)(CHO)). As your book says, simple ketones have distinctive odors (similar to acetone) that are typically not unpleasant in low doses. Like aldehydes, placing a collection of double bonds adjacent to a ketone carbonyl generally makes the substance more fragrant. The primary flavoring agent in oil of caraway is just a such a ketone. 2 O oil of carraway Because the C=O group is polar, small aldehydes and ketones enjoy significant water solubility. They are also quite soluble in typical organic solvents. 14.2 Naming Aldehydes and Ketones Aldehydes The IUPAC names for aldehydes are obtained by using rules similar to those we’ve seen for other functional groups (e.g.
    [Show full text]
  • Unusual Regioselectivity in the Opening of Epoxides by Carboxylic Acid Enediolates
    Molecules 2008, 13, 1303-1311 manuscripts; DOI: 10.3390/molecules13061303 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.org/molecules Communication Unusual Regioselectivity in the Opening of Epoxides by Carboxylic Acid Enediolates Luis R. Domingo, Salvador Gil, Margarita Parra* and José Segura Department of Organic Chemistry, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Spain. Fax +34(9)63543831; E-mails: [email protected]; [email protected]; [email protected] * Author to whom correspondence should be addressed; E-mail: [email protected] Received: 29 May 2008; in revised form: 5 June 2008 / Accepted: 6 June 2008 / Published: 9 June 2008 Abstract: Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol) for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpectedly, to a mixture resulting from the attack on both the primary and secondary carbon atoms. Generally, a low diastereoselectivity is seen on attack at the primary center, however only one diastereoisomer was obtained from attack to the secondary carbon of the styrene oxide. Keywords: Lactones, lithium chloride, nucleophilic addition, regioselectivity, diastereoselectivity. Introduction Epoxides have been recognized among the most versatile compounds in organic synthesis, not only as final products [1] but as key intermediates for further manipulations. Accordingly, new synthetic developments are continuously being published [2]. Due to its high ring strain (around 27 Kcal/mol) its ring-opening, particularly with carbon-based nucleophiles, is a highly valuable synthetic strategy Molecules 2008, 13 1304 [3].
    [Show full text]
  • Highly Efficient Epoxidation of Olefins with Hydrogen Peroxide Oxidant Using Modified Silver Polyoxometalate Catalysts
    African Journal of Pure and Applied Chemistry Vol. 7(2), pp. 50-55, February 2013 Available online at http://www.academicjournals.org/AJPAC DOI: 10.5897/AJPAC12.060 ISSN 1996 - 0840 ©2013 Academic Journals Full Length Research Paper Highly efficient epoxidation of olefins with hydrogen peroxide oxidant using modified silver polyoxometalate catalysts Emmanuel Tebandeke 1*, Henry Ssekaalo 1 and Ola F. Wendt 2 1Department of Chemistry, Makerere University, P. O. Box 7062 Kampala, Uganda. 2Organic Chemistry, Department of Chemistry, Lund University, P. O. Box 124, 221 00 Lund, Sweden. Accepted 31 January, 2013 The catalytic epoxidation of olefins is an important reaction in chemical industry since epoxides are versatile and important intermediates in the synthesis of fine chemicals and pharmaceuticals. The current epoxidation procedures often use stoichiometric organic and sometimes toxic inorganic oxidants that are less favourable from an environmental and economical point of view. In contrast to such processes, catalytic epoxidation processes employing H2O2 oxidant are preferred for green processing. Herein is reported a highly efficient green process for the epoxidation of olefins using H2O2 oxidant and modified silver polyoxometalate catalysts at 65°C. The preparation and activity of the catalysts are described. The method enjoys >90% conversion and ≥99% selectivity to the epoxide for a variety of cyclic and linear olefins including terminal ones. The catalysts are easily recovered by filtration and are reusable several times. Key words: Epoxidation, olefins, hydrogen peroxide, polyoxometalate, silver catalysts. INTRODUCTION The catalytic epoxidation of olefins is very important in compared to organic peroxides and peracids (Jones, the chemical industry since epoxides are versatile and 1999; Lane and Burgess, 2003).
    [Show full text]
  • Reactions of Benzene & Its Derivatives
    Organic Lecture Series ReactionsReactions ofof BenzeneBenzene && ItsIts DerivativesDerivatives Chapter 22 1 Organic Lecture Series Reactions of Benzene The most characteristic reaction of aromatic compounds is substitution at a ring carbon: Halogenation: FeCl3 H + Cl2 Cl + HCl Chlorobenzene Nitration: H2 SO4 HNO+ HNO3 2 + H2 O Nitrobenzene 2 Organic Lecture Series Reactions of Benzene Sulfonation: H 2 SO4 HSO+ SO3 3 H Benzenesulfonic acid Alkylation: AlX3 H + RX R + HX An alkylbenzene Acylation: O O AlX H + RCX 3 CR + HX An acylbenzene 3 Organic Lecture Series Carbon-Carbon Bond Formations: R RCl AlCl3 Arenes Alkylbenzenes 4 Organic Lecture Series Electrophilic Aromatic Substitution • Electrophilic aromatic substitution: a reaction in which a hydrogen atom of an aromatic ring is replaced by an electrophile H E + + + E + H • In this section: – several common types of electrophiles – how each is generated – the mechanism by which each replaces hydrogen 5 Organic Lecture Series EAS: General Mechanism • A general mechanism slow, rate + determining H Step 1: H + E+ E El e ctro - Resonance-stabilized phile cation intermediate + H fast Step 2: E + H+ E • Key question: What is the electrophile and how is it generated? 6 Organic Lecture Series + + 7 Organic Lecture Series Chlorination Step 1: formation of a chloronium ion Cl Cl + + - - Cl Cl+ Fe Cl Cl Cl Fe Cl Cl Fe Cl4 Cl Cl Chlorine Ferric chloride A molecular complex An ion pair (a Lewis (a Lewis with a positive charge containing a base) acid) on ch lorine ch loronium ion Step 2: attack of
    [Show full text]
  • Synthesis of Densely Substituted Pyridine Derivatives from Nitriles by a Non-Classical [4+2] Cycloaddition/1,5-Hydrogen Shift Strategy
    Synthesis of densely substituted pyridine derivatives from nitriles by a non-classical [4+2] cycloaddition/1,5-hydrogen shift strategy Wanqing Wu ( [email protected] ) South China University of Technology https://orcid.org/0000-0001-5151-7788 Dandan He South China University of Technology Kanghui Duan South China University of Technology Yang Zhou South China University of Technology Meng Li South China University of Technology Huanfeng Jiang South China University of Technology Article Keywords: pyridine derivatives, organic synthesis, medicinal chemistry. Posted Date: March 3rd, 2021 DOI: https://doi.org/10.21203/rs.3.rs-258126/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/18 Abstract A novel strategy has been established to assemble an array of densely substituted pyridine derivatives from nitriles and o-substituted aryl alkynes or 1-methyl-1,3-enynes via a non-classical [4 + 2] cycloaddition along with 1,5-hydrogen shift process. The well-balanced anities of two different alkali metal salts enable the C(sp3)-H bond activation as well as the excellent chemo- and regioselectivities. This protocol offers a new guide to construct pyridine frameworks from nitriles with sp3-carbon pronucleophiles, and shows potential applications in organic synthesis and medicinal chemistry. Introduction Compounds containing pyridine core structures, not only widely exist in natural products, pharmaceuticals, and functional materials,1–7 but also serve as useful and valuable building blocks for metal ligands.8,9 For instance, pyridine derivative Actos I10 is a famous drug for the treatment of type 2 diabetes; Bi-(or tri-)pyridines II11–15 are often used as ligands in metal-catalyzed reactions; Kv1.5 antagonist III16 and alkaloid papaverine IV17 are two representative isoquinolines as a promising atrial- selective agent and a smooth muscle relaxant, respectively (Fig.
    [Show full text]