The acetoacetic ester synthesis is a carbonyl alkylation reaction. It is used to prepare methyl ketones from primary alkyl halides, lengthening the carbon chain by three atoms. Thus, the product can be visualized as being a "substituted acetone." The reaction consists of three steps: generation of the enolate anion followed by SN2 reaction with a primary alkyl halide, ester hydrolysis under acid conditions, and decarboxylation. м Br H3C H3C OEt 1. NaOEt 2. H₂O* 3. heat H₂C. Draw curved arrows to show the movement of electrons in this step of the mechanism. CO₂ EtOH CH3 Arrow-pushing Instructions H3C 1:0: :0: :Br: Br: H₂C CH3 CH3 H3C CH3 7b

The acetoacetic ester synthesis is a carbonyl alkylation reaction. It is used to prepare methyl ketones from primary alkyl halides, lengthening the carbon chain by three atoms. Thus, the product can be visualized as being a "substituted acetone." The reaction consists of three steps: generation of the enolate anion followed by SN2 reaction with a primary alkyl halide, ester hydrolysis under acid conditions, and decarboxylation. м Br H3C H3C OEt 1. NaOEt 2. H₂O* 3. heat H₂C. Draw curved arrows to show the movement of electrons in this step of the mechanism. CO₂ EtOH CH3 Arrow-pushing Instructions H3C 1:0: :0: :Br: Br: H₂C CH3 CH3 H3C CH3 7b

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter19: Enolate Anions And Enamines

Section: Chapter Questions

Problem 19.40P: Enamines normally react with methyl iodide to give two products: one arising from alkylation at...

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The acetoacetic ester synthesis is a carbonyl alkylation reaction. It is used to prepare methyl ketones from primary alkyl halides, lengthening the carbon chain by three atoms. Thus, the product can be visualized as being a "substituted acetone." The reaction consists of three steps: generation of the enolate anion followed by SN2 reaction with a primary alkyl halide, ester hydrolysis under acid conditions, and decarboxylation. Br H₂C H3C 1. NaOEt 2. H₂O* 3. heat H₂C. OEt Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions H X CO2 CH3 + EtOH :OH На CH3 CO2 CH3 CH3 CH3
CH3 Ph3P-CHCH3 H3C H3C Aldehydes and ketones are converted into alkenes by means of a direct nucleophilic addition called the Wittig reaction. In the reaction, a triphenylphosphorine ylide, also called a phosphorane, adds to an aldehyde/ketone to give a four-membered cyclic intermediate called an oxaphosphetane. The oxaphosphetane is not isolated but instead spontaneously decomposes to release triphenylphosphine oxide and an alkene. Ph3P-CHCH3 H3C The ylide is formed by reaction of triphenylphosphine, a good nucleophile, with a primary alkyl halide in an S 2 reaction, followed by deprotonation of the carbon with a strong base, such as butyllithium. The carbonyl carbon and the carbon originally bonded to the halogen become the two carbons with the double bond in the product alkene :0: CH3 Com The real value of the Wittig reaction lies in its ability to yield an alkene of predictable structure, as the C-C bond is precisely where the C=O bond was in the reactant and no isomers (other than…
Ph3P-CHCH3 H₂C H3C Aldehydes and ketones are converted into alkenes by means of a direct nucleophilic addition called the Wittig reaction. In the reaction, a triphenylphosphorine ylide, also called a phosphorane, adds to an aldehyde/ketone to give a four-membered cyclic intermediate called an oxaphosphetane. The oxaphosphetane is not isolated but instead spontaneously decomposes to release triphenylphosphine oxide and an alkene. CH3 00 + The ylide is formed by reaction of triphenylphosphine, a good nucleophile, with a primary alkyl halide in an SN2 reaction, followed by deprotonation of the carbon with a strong base, such as butyllithium. The carbonyl carbon and the carbon originally bonded to the halogen become the two carbons with the double bond in the product alkene X m CH3 The real value of the Wittig reaction lies in its ability to yield an alkene of predictable structure, as the C=C bond is precisely where the C=O bond was in the reactant and no isomers (other than E/Z isomers)…
Alkynes do not react directly with aqueous acid as do alkenes, but will do so in the presence of mercury(II) sulfate as a Lewis acid catalyst. The reaction occurs with Markovnikov regiochemistry, so the OH group adds to the more highly substituted carbon and the H adds to the less highly substituted carbon. The initial product of the reaction is a vinyl alcohol, also called an enol. The enol immediately rearranges to a more stable ketone via tautomerization. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions -X티 Hö: H-O -CH3 -CH3 H30*
Br Brz CH3 CH3 H3C CH2CI2 H3C Br Electrophilic addition of bromine, Br2; to alkenes yields a 1,2-dibromoalkane. The reaction proceeds through a cyclic intermediate known as a bromonium ion. The reaction occurs in an anhydrous solvent such as CH,Cl). In the second step of the reaction, bromide is the nucleophile and attacks at one of the carbons of the bromonium ion to yield the product. Due to steric clashes, the bromide ion always attacks the carbon from the opposite face of the bromonium ion so that a product with anti stereochemistry is formed. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions Br: :Br: .CH3 H3C H3C CH3 Br:
Give the major organic products from the following reactions
Provide the reagent(s) and the reaction mechanism of the following reaction H₂N
Diphenylacetylene can be synthesized by the double dehydrohalogenation of 1,2-dibromo-1,2-diphenylethene. The sequence starting from (E)-1,2-diphenylethene consists of bromination to give the dibromide, followed by dehydrohalogenation to give a vinylic bromide, then a second dehydrohalogenation to give diphenylacetylene.(a) What is the structure, including stereochemistry, of the vinylic bromide?(b) If the sequence starts with (Z)-1,2-dibromo-1,2-diphenylethene, what is (are) the structure(s) of the intermediate dibromide(s)? What is the structure of the vinylic bromide?
The following substances can be prepared by a nucleophilic addition reaction between an aldehyde or ketoneand a nucleophile. Identify the reactants from which they were prepared. If the substance is an acetal, identifythe carbonyl compound and the alcohol; if it is an imine or enamine, identify the carbonyl compound and theamine. You do not have to consider stereochemistry. In cases where there is more than one answer, just giveone. Use Grignard reagents when an organometallic reagent is required. Draw the Grignard reagent as acovalent magnesium bromide.
Complete the reaction schemes below providing the reagents required to achieve thetransformation. More than one step may be necessary for each scheme.
Please provide a step by step list explaining the mechanism for the reactions
Alkyl halides undergo nucleophilic substitution and elimination reactions. When the kinetics of the reaction are measured, if the rate of the reaction is found to be dependent only upon the concentration of the alkyl halide the reaction is first order. The substitution reaction is thus termed SN1, and the elimination reaction is termed E1. These reactions are unimolecular and occur in two steps. The first step is rate-limiting and involves the loss of the leaving group to form a carbocation. In the second, fast, step the nucleophile adds to the carbocation in the SN1 reaction or elimination occurs to give an alkene in the E1 reaction. Because the carbocation is planar, the nucleophile can add to either face and therefore racemization is usually observed although solvent effects can influence this somewhat. E1 elimination follows Zaitsev’s rule and typically yields the most substituted alkene as the major product. Conditions which favor the SN1/E1 pathway include the use of a weak…