Interpretation:
The mechanism for the given reaction between 2,3-dimethyl-1,3-butadiene and hydrogen bromide is to be determined. The reaction energy coordinate diagram that illustrates kinetic and thermodynamic pathways is to be drawn.
Concept introduction:
舧 Electrophiles are electron-deficient species, which has positive or partially positive charge. Lewis acids are electrophiles, which accept electron pair.
舧 Nucleophiles are electron-rich species, which has negative or partially negative charge. Lewis bases are nucleophiles, which donate electron pair.
舧 Free radical is an atom, molecule, or ion that has an unpaired electron, which makes it highly chemically reactive.
舧 Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a
舧 Elimination reaction: A reaction in which two substituent groups are detached and a double bond is formed is called elimination reaction.
舧 Addition reaction: It is the reaction in which unsaturated bonds are converted to saturated molecules by the addition of molecules.
舧 The reaction in which there is addition of hydrogen molecule is called hydrogenation reaction.
舧
舧 Hydrogenation with platinum as a catalyst is used to convert unsaturated carbohydrates to saturated hydrocarbons
舧 Oxidation of
舧 Ozonolysis helps convert the carbon – carbon double bonds to carbon – oxygen double bond (carbonyl compounds).
舧 Dimethyl sulfide is used as a reducing agent that decomposes the intermediate formed into the carbonyl group.
舧 NBS (nitro-bromo succinimide) is a special reagent used for bromination of allylic carbocations.
舧 Bromine replaces the hydrogen attached to the carbon adjacent to the carbon bearing double bond.
舧 This method of using NBS can produce allylic bromides without bromine reacting with the double bond.
舧 Dehydration of a primary alcohol in the presence of a mineral acid like concentrated sulfuric acid results in the formation of alkene via E2 elimination.
舧 1,2–addition of hydrohalogenation (HX) to a diene is the addition of hydrogen to the carbon designated as 1 and halogen to the carbon designated as 2. The positions of carbon as 1 and 2 are not according to the IUPAC numbering of the molecule, but as a conjugated diene. The mechanism is similar to 1,4-addition. The mechanism of 1,2-addition and 1,4-addition of hydrohalogenation is given below:
舧 When conjugated diene is attacked by an electrophile, the resultant products are formed via 1,2-addition and 1,4-addition reaction mechanism. Kinetics and
Want to see the full answer?
Check out a sample textbook solution
Chapter 13 Solutions
Organic Chemistry
- Propose a mechanism for the following reaction, an important step in the laboratory synthesis of proteins:arrow_forwardThe following molecule undergoes an intramolecular reaction in the presence of pyrrolidinium acetate, the protonated form of pyrrolidine. Draw the product of this reaction, assuming that a dehydration reaction takes place.arrow_forwardA problem often encountered in the oxidation of primary alcohols to acids is that esters are sometimes produced as by-products. For example, oxidation of ethanol yields acetic acid and ethyl acetate: Propose a mechanism to account for the formation of ethyl acetate. Take into account the reversible reaction between aldehydes and alcohols:arrow_forward
- Nonconjugated , -unsaturated ketones, such as 3-cyclohexenone, are in an acid-catalyzed equilibrium with their conjugated , -unsaturated isomers. Propose a mechanism for this isomerization.arrow_forwardPlease complete the reactions given below.arrow_forwardDraw the organic product expected from the reaction. Include all hydrogen atoms. Note that K2Cr2O7K2Cr2O7 is present in excess. CH3CH2CH2OH+K2Cr2O7(aq) −→−−−H2SO4arrow_forward
- Acyl transfer (nucleophilic substitution at carbonyl) reactions proceed in two stages via a "tetrahedral intermediate." Draw the tetrahedral intermediate as it is first formed in the following reaction. You do not have to consider stereochemistry. Include all valence lone pairs in your answer. Do not include counter-ions, e.g., Na+, I-, in your answer. In cases where there is more than one answer, just draw one.arrow_forwardAcyl transfer (nucleophilic substitution at carbonyl) reactions proceed in two stages via a "tetrahedral intermediate." Draw the tetrahedral intermediate as it is first formed in the following reaction. You do not have to consider stereochemistry. Include all valence lone pairs in your answer. Do not include counter-ions, e.g., Na+, I-, in your answer. In cases where there is more than one answer, just draw one.arrow_forwardFor each reaction, give the expected substitution product, and predict whether the mechanism will be predominantly first order (SN1) or second-order (SN2). (a) isobutyl bromide + sodium methoxidearrow_forward
- (b) Consider the reaction of 1-bromobutane with a large excess of ammonia (NH3). Draw the reactants, the transition state, andthe products. Note that the initial product is the salt of an amine (RNH3+ Br - ), which is deprotonated by the excess ammonia to give the amine.arrow_forward1) Draw an arrow-pushing mechanism for the reaction shown below. 1) xs 2) H₂O MgBr HO OHarrow_forwardDraw the structure of unsaturated carbonyl compound(s) formed when 3-Hydroxy-2,4-diphenyl-butyraldehyde is heatedin i) a basic ii) an acidic solution. iii) Write the complete mechanism for the dehydration reaction that takes place in the basic solution.arrow_forward
Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning
Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning