Concept explainers
Interpretation:
A mechanism for the reversible equilibrium isomerization of 2-substituted-2-cyclopentanones to 5-substituted-2-cyclopentanones is to be proposed.
Concept introduction:
The steps involved in the reversible equilibrium isomerization of 2-substituted-2-cyclopentanones to 5-substituted-2-cyclopentanones are i) abstraction of a proton from the γ-carbon to form a resonance stabilized enolate ion ii) Protonation at the α- carbon iii) Abstraction of a proton from other α- carbon to form a different resonance stabilized enolate ion iv) Protonation of the γ- carbon.
To propose
A mechanism for the reversible equilibrium isomerization of 2-substituted-2-cyclopentanones to 5-substituted-2-cyclopentanones.
Trending nowThis is a popular solution!
Chapter 22 Solutions
Organic Chemistry
- 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_forwardPropose a synthesis of the topical anesthetic cyclomethycaine from 4-hydroxybenzoic acid, 2-methylpiperidine, and any other necessary reagents. HN' + HO. НО Cyclomethycaine 4-Hydroxybenzoic acid 2-Methylpiperidinearrow_forwardWhich one of the following carboxylic acid derivatives can undergo nucleophilic acyl substitution without the need of an acid to catalyze the reaction? O CH3C=N ОН `NH2arrow_forward
- Treatment of 1-aminoadamantane, C10H17N, with methyl 2,4-dibromobutanoate in the presence of a nonnucleophilic base, R3N, involves two successive SN2 reactions and gives compound A. Propose a structural formula for compound A.arrow_forwardEthylene oxide is the starting material for the synthesis of 1,4-dioxane. Propose a mechanism for each step in this synthesis.arrow_forwardCyclohexene can be converted to 1-cyclopentenecarbaldehyde by the following series of reactions. Propose a structural formula for each intermediate compound.arrow_forward
- Dihydropyran is synthesized by treating tetrahydrofurfuryl alcohol with an arenesulfonic acid, ArSO3H. Propose a mechanism for this conversion.arrow_forwardA step in a synthesis of PGE1 (prostaglandin E1, alprostadil) is the reaction of a trisubstituted cyclohexene with bromine to form a bromolactone. Propose a mechanism for formation of this bromolactone and account for the observed stereochemistry of each substituent on the cyclohexane ring. Alprostadil is used as a temporary therapy for infants born with congenital heart defects that restrict pulmonary blood flow. It brings about dilation of the ductus arteriosus, which in turn increases blood flow in the lungs and blood oxygenation.arrow_forwardWhen cis-2-decalone is dissolved in ether containing a trace of HCl, an equilibrium is established with trans-2-decalone. The latter ketone predominates in the equilibrium mixture. Propose a mechanism for this isomerization and account for the fact that the trans isomer predominates at equilibrium.arrow_forward
- Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism:arrow_forwardAll 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_forwardOne frequently used method for preparing methyl esters is by reaction of carboxylic acids with diazomethane, CH2N2. The reaction occurs in two steps: (l) protonation of diazomethane by the carboxylic acid to yield methyldiazonium ion, CH3N2+, plus a carboxylate ion; and (2) reaction of the carboxylate ion with CH3N2+. (a) Draw two resonance structures of diazomethane, and account for step 1. (b) What kind of reaction occurs in step 2?arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningIntroduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning
- EBK A SMALL SCALE APPROACH TO ORGANIC LChemistryISBN:9781305446021Author:LampmanPublisher:CENGAGE LEARNING - CONSIGNMENT