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104 Chapter 22: Amines. Organic derivatives of ammonia, NH3
104 Chapter 22: Amines. Organic derivatives of ammonia, NH3

... Alkyl ammonium ions, R3NH+ X-, have pKa values in the range of 10-11 (ammonium ion, H4N+ X-, has a pKa ~ 9.3) The ammonium ions of aryl amines and heterocyclic aromatic amines are considerably more acidic than alkyl amines (pKa < 5). The nitrogen lone pair is less basic if it is in an sp2 hybridized ...
organic compound containing nitrogen
organic compound containing nitrogen

... We shall compare the stabilities of amines with the stabilities of their ions; the more stable the ion relative to the amine from which it is formed, the more basic the amine. First of all, amines are more basic than alcohols, ethers, esters etc. for the same reason that ammonia is more basic than w ...
Chapter 10 - UCSB CLAS
Chapter 10 - UCSB CLAS

... Basic or Neutral (SN2) ⇒ 1° > 2° > 3° IV. Arene Oxides ⇒ In this chapter you will see arene oxides undergoing either nucleophilic substitution reactions same as epoxides in basic/neutral conditions or rearrangement reactions to produce phenol (primary focus) – since there’s a carbocation formed in t ...
Chapter 24. Amines
Chapter 24. Amines

... Gabriel Synthesis of Primary Amines • A phthalimide alkylation for preparing a primary amine from an alkyl halide • The N-H in imides (CONHCO) can be removed by KOH followed by alkylation and ...
Chapter 24. Amines
Chapter 24. Amines

... Gabriel Synthesis of Primary Amines • A phthalimide alkylation for preparing a primary amine from an alkyl halide • The N-H in imides (CONHCO) can be removed by KOH followed by alkylation and ...
CHAPTER 21 PHENOLS AND ARYL HALIDES
CHAPTER 21 PHENOLS AND ARYL HALIDES

... acidic than water. OH + NaOH ...
Reaction of orthoesters with alcohols in the presence of acidic
Reaction of orthoesters with alcohols in the presence of acidic

... excess of orthoester in order to improve the yield). Even though reaction of orthoesters with various carbonyl functions such as ketones, aldehydes, carboxylic as well as sulphonic acids were studied in detail in the past, 5, 6 this study pertaining to alcohols is only limited to Claisen-Johnson rea ...
Class 15
Class 15

... 2) Start numbering from the end closest to the alcohol ...
Chemdraw B&W - Chemistry Courses
Chemdraw B&W - Chemistry Courses

... • Amides (RCONH2) in general are not proton acceptors except in very strong acid • The C=O group is strongly electron-withdrawing, making the N a very weak base • Addition of a proton occurs on O but this destroys the double bond character of C=O as a requirement of ...
Chapter 24. Amines
Chapter 24. Amines

... Azo-coupled products have extended  conjugation that lead to low energy electronic transitions that occur in visible light (dyes) ...
Document
Document

... d. Nucleophilic substitution of -halo acids with NH3 (Ch. 20.15) ...
Chapter 24. Amines
Chapter 24. Amines

...  Most amines that have 3 different substituents on N are not resolved because the molecules interconvert ...
Chapter 24. Amines - Houston Community College System
Chapter 24. Amines - Houston Community College System

...  Most amines that have 3 different substituents on N are not resolved because the molecules interconvert ...
Enantioselective Organocatalytic Aminomethylation of Aldehydes: A
Enantioselective Organocatalytic Aminomethylation of Aldehydes: A

... tions provide evidence that non-H-bonded ionic interactions at the Mannich reaction transition state can influence stereochemical outcome. Formaldehyde does not form stable imines,5 so we examined formaldehyde derivatives, such as A, that can generate a methylene iminium species in situ.6 We examine ...
Chapter 20: Carboxylic Acids and Nitriles
Chapter 20: Carboxylic Acids and Nitriles

... An amine with three different substituents on nitrogen is chiral (in principle but not in practice): the lone pair of electrons is the fourth substituent Most amines that have 3 different substituents on N are not resolved because the molecules interconvert by ...
Organocatalysed asymmetric Mannich reactions
Organocatalysed asymmetric Mannich reactions

... cases existed, by the end of the last century numerous successful examples of asymmetric organocatalytic reactions had been developed.1 In this tutorial review we aim to address organocatalytic versions of the well-known Mannich reaction in particular.2 A key element in Mannich reactions is an imini ...
Rhenium(VII) Catalysis of Prins Cyclization Reactions
Rhenium(VII) Catalysis of Prins Cyclization Reactions

... more complex aldehyde 17, prepared by a metathesis reaction between crotonaldehyde and the corresponding terminal alkene, was noticeably slower than the others. All of the products showed very good selectivity for the equatorial alcohol THP products. Unsaturated aldehydes will be useful for forming ...
Synthesis of (−)-Epibatidine - David A. Evans
Synthesis of (−)-Epibatidine - David A. Evans

... Although the reduction proceeded without affecting the chloropyridine ring,21 a 75:25 mixture of inseparable alcohols was obtained. The structural assignment of the major diastereomer was complicated as a result of slowly interconverting conformations as observed by 1H NMR spectroscopy, even at elev ...
3672 been studied in detail by Kebarle, et al., who
3672 been studied in detail by Kebarle, et al., who

... with both disulfides’ and peroxidess have been demonstrated to follow a mechanistically similar pathway. In direct analogy with these systems, the reaction of trimethyl phosphite with a sulfenate ester could, a priori, lead to the pentacoordinate phosphorane 1 and (or) the phosphonium salts 2-4 whic ...
Handout 7
Handout 7

... protecting aldehyde and ketone groups from undesired reactions in basic solutions. We can convert an aldehyde or ketone to acetal or cyclic ketal, carry out a reaction on some other part of the molecule, and then hydrolyze the acetal or ketal with aqueous acid. As an example, let us consider the pro ...
Summer Scholar Report
Summer Scholar Report

... A method for synthesis of allylic tosylates from allylic alcohols was developed that does not require metal catalysis or harsh conditions. The method was also utilized to produce
 secondary tosylates from their parent alcohols. Sodium hydride was used to generate the alkoxide, which can then be trea ...
CN>Chapter 22CT>Carbonyl Alpha
CN>Chapter 22CT>Carbonyl Alpha

... Synthesis of carboxylic acids using malonic ester via the decarboxylation of malonic acid  The malonic ester synthesis converts an alkyl halide into a ...
Micellar Catalytic Effect of Cetyltrimethylammonium Bromide
Micellar Catalytic Effect of Cetyltrimethylammonium Bromide

... Because of that the use of heat on allylation of eugenol should be avoided. To avoid using heat, reaction could be conduct in room temperature, since reaction of ether formation involves two phase, so reaction could be done by phase transfer catalyst or micellar catalyst. Previous research that has ...
Methodology for the olefination of aldehydes and ketones via the Meyer-Schuster reaction
Methodology for the olefination of aldehydes and ketones via the Meyer-Schuster reaction

... Phosphorus ylides are prepared before the reaction or in-situ and precautions must be taken due to their sensitivity to moisture and air. The carbanion of the ylide is the characteristic component that allows for nucleophilic attack on the carbonyl carbon. The ylides have been found to demonstrate ...
Origin of the Diastereoselection in the Indium
Origin of the Diastereoselection in the Indium

... being inserted. This was presumably the reason that the geometry of the CdC bond of 1 was not important in controlling the stereoselectivity of the In-mediated addition reaction. The energy difference between the conformations A and B would thus decide the ratio of anti-3/syn-3. There might be a ver ...
< 1 2 3 4 >

Aza-Cope rearrangement

Rearrangements, especially those that can participate in cascade reactions, such as the aza-Cope rearrangements, are of high practical as well as conceptual importance in organic chemistry, due to their ability to quickly build structural complexity out of simple starting materials. The aza-Cope rearrangements are examples of heteroatom versions of the Cope rearrangement, which is a [3,3]-sigmatropic rearrangement that shifts single and double bonds between two allylic components. In accordance with the Woodward-Hoffman rules, thermal aza-Cope rearrangements proceed suprafacially. Aza-Cope rearrangements are generally classified by the position of the nitrogen in the molecule (see figure): The first example of an aza-Cope rearrangement was the ubiquitous cationic 2-aza-Cope Rearrangement, which takes place at temperatures 100-200 °C lower than the Cope rearrangement due to the facile nature of the rearrangement. The facile nature of this rearrangement is attributed both to the fact that the cationic 2-aza-Cope is inherently thermoneutral, meaning there's no bias for the starting material or product, as well as to the presence of the charged heteroatom in the molecule, which lowers the activation barrier. Less common are the 1-aza-Cope rearrangement and the 3-aza-Cope rearrangement, which are the microscopic reverse of each other. The 1- and 3-aza-Cope rearrangements have high activation barriers and limited synthetic applicability, accounting for their relative obscurity.To maximize its synthetic utility, the cationic 2-aza-Cope rearrangement is normally paired with a thermodynamic bias toward one side of the rearrangement. The most common and synthetically useful strategy couples the cationic 2-aza-Cope rearrangement with a Mannich cyclization, and is the subject of much of this article. This tandem aza-Cope/Mannich reaction is characterized by its mild reaction conditions, diastereoselectivity, and wide synthetic applicability. It provides easy access to acyl-substituted pyrrolidines, a structure commonly found in natural products such as alkaloids, and has been used in the synthesis of a number of them, notably strychnine and crinine.Larry E. Overman and coworkers have done extensive research on this reaction.
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