Concept explainers
Interpretation:
The effect of alkene structure on the rate of the overall reaction is to be predicted.
Concept Introduction:
>The transition state for proton transfer from
This means that the more stable carbocation must be formed preferentially.
>The more stable carbocation is the one having the more substituents attached to the carbon atom bearing the positive charge.
>In general, tertiary carbocations are more stable as compared to secondary and primary carbocations.
>Once the carbocation is formed, the halide ion gets attached to the carbon bearing the positive charge, forming the
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Organic Chemistry - Standalone book
- All rearrangements we have discussed so far have involved generation of an electron-deficient carbon followed by a 1,2-shift of an atom or a group of atoms from an adjacent atom to the electron-deficient carbon. Rearrangements by a 1,2-shift can also occur following the generation of an electron-deficient oxygen. Propose a mechanism for the acid-catalyzed rearrangement of cumene hydroperoxide to phenol and acetone.arrow_forward10) Synthesis: Make the following products from a suitable cyclic alkene starting material. Look at the functional group PATTERN present in the molecule, including stereochemistry. Br CH3 Br CH3arrow_forwardDraw the most stable resonance form for the intermediate in the following electrophilic substitution reaction. CH3 CH3 H3PO4 HO, + H3C CH3 HO HO First stage in synthesis of the epoxy and polycarbonate ingredient bisphenol-A You do not have to consider stereochemistry. Include all valence lone pairs in your answer. In cases where there is more than one answer, just draw one.arrow_forward
- 2. The following carbocation is generated as an intermediate in the addition of H-Br to an alkene. Draw the structure of all possible alkenes that could have formed this intermediate.arrow_forwardWrite a mechanism that accounts for the formation of ethyl isopropyl ether as one of the products in the following reaction. CI OEt HCI EtOH Write the mechanism for step one of this reaction. Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. Write the mechanism for step two of this reaction (where the product of step one reacts with the solvent, ethanol). Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. Write the mechanism for the last step of this reaction (formation of ethyl isopropyl ether). Show lone pairs and formal charges. Only the acidic hydrogen should be drawn out with a covalent bond. CI will act as the base in this reaction.arrow_forwardSelect the possible major product in the given reaction. 41. Dehydration of alcohols 42. Elimination of H-X in alkylhalides 43. Reaction of alcohols and carboxylic acids 44. Reduction of aldehydes 45. Substitution of reaction between ROH and SOCI, Choices: (A) 1 ROH (B) 2 ROH (C) 3 ROH (D) Alkene RCHO (E) (AB) RCOOH (AC) RCOR' (AD) RX Which of the following reagent (s) are needed in the following reactions? 46. Reduction of carboxylic acids to primary alcohols 47. Oxidation of primary alcohols to aldehydes 48. Reduction of ketones to secondary alcohols 49. Saponification of esters 50. Dehydration of alcohols Choices: aqueous NAOH and heat (B) Hạ in Pt (C) (A) H;O, H;SO, (D) H,SO, with heat (E) K,Cr,O, and H,So, (АB) LIAIH, (AC) PCC (AD) Tollens' reagentarrow_forward
- 6) You have decided to repeat the reaction from Question 5 using a slightly different alkene starting material. You now observe 3 products, and you suspect that your major product (Product A) is the result of a carbocation rearrangement. Draw the mechanism for the formation of Product A and indicate which type of carbocation rearrangement has occurred. H₂O H₂SO4 A OH 67% Major Product B OH 32% Minor Product C 1% OHarrow_forwardChoose reagents to convert 2-cyclohexenone to the following compounds. Syntheses may require several steps. Use letters from the table to list reagents in the order used (first at the left). i 1. Li(CH2=CH)2Cu Reagents a 1. Li(CH3)2Cu 2. H3O+ e 1. Li(C6H5)2Cu 2. H3O+ b 1. NaBH4 f CH2l2/Zn(Cu) / ether j 2. H3O+ C NH3 / KOH g 1. CH3MgBr/dry ether k 2 H3O+ d H2NNH2/KOH h HN(CH3)2 HO CH3 a) b) OH N(CH3)2 2. H3O+ (C6H5)3P+-CH2 H₂ over Pd/C KMnO4/H3O+arrow_forwardBr 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:arrow_forward
- CH3 CH3 Br- Br2 .CH3 CH2Cl2 CH3 H3C H3C Br Electrophilic addition of bromine, Brɔ, 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 CH3 CH3 CH3 CH3 H3C H3C :Br: :Br:arrow_forwardThe reaction shown below is carried out in two stages. In the first, the two reactants are combined in tetrahydrofuran (THF) solvent to form a neutral adduct. Aqueous acid is then added to hydrolyze this initial adduct, giving the final product. N(CH3)2 I. H a For the reaction shown above, draw the major organic product having at least one carbonyl group. • You do not have to consider stereochemistry. Pis 85 1. THF 2. H3O+ n [ ]#arrow_forwardSelect the reagent that you would use to convert an alkene to a Markovnikov (more substituted) alcohol without possibility of carbocation rearrangement. o H2SO4, H2O OBH3-THF, then H2O2, H2O, NaOH Hg(OAc)2, H2O, then NaBH4 o OsO4, TBHP, H2Oarrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning