Organic Chemistry 1 · Unsaturated molecules and radicals
Alkene addition and regiochemistry: practice problems
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- Protonate an exocyclic double bond
- Oxymercuration–demercuration of 1-methylcyclohexene
- Build the ionic addition sequence
- Move a neighboring bond
- Hydrate a branched alkene
- An alcohol solvent changes the product
- Markovnikov hydration — with a hydride shift
- Retain a migrating carbon through addition
- Move a double bond without adding oxygen
Draw the mechanism 142
- Build the ionic addition sequenceTrack both electron pairs during HX addition and capture the carbocation.
- Move a neighboring bondDistinguish hydride migration from proton transfer and relocate a carbocation.
- Hydrate a branched alkeneComplete acid-catalyzed hydration through a tertiary cation and regenerate the acid.
- An alcohol solvent changes the productUse a neutral alcohol rather than water to capture an alkene-derived cation and recover a neutral ether.
- Markovnikov hydration — with a hydride shiftUse a C–H bond pair in a hydride shift, then add water and give back a proton to make the alcohol.
- Retain a migrating carbon through additionComplete HX addition with a skeletal rearrangement where the neighboring quaternary carbon cannot donate hydride.
- Move a double bond without adding oxygenDistinguish acid-catalyzed alkene isomerization from net hydration and track exchanged hydrogens.
- Let the tether choose a ringComplete intramolecular alkene hydroalkoxylation and count the five-membered ether ring.
- Account for an isotopic acid labelLocate deuterium and chloride independently using carbocation stability rather than replacing an existing carbon hydrogen.
- Halohydrin formation — styrene, Br₂ and waterOpen a bromonium bridge with water, then remove a proton to make the alcohol.
- Capture a bridge in an alcohol mediumComplete bromomethoxylation, selecting the bridge-opening site and accounting for the alcohol proton.
- Follow an oxygen-substituted alkene to a carbonylComplete enol-ether hydrolysis through a hemiacetal, including leaving-group activation and carbonyl formation.
- Add HBr and let a hydride moveRecognize that the secondary cation from HBr addition can become tertiary through a 1,2-hydride shift before bromide bonds.
- Grow a strained ring during HCl additionUse a ring-bond migration that relieves four-membered-ring strain and upgrades a secondary cation to a tertiary one.
- Add HCl to a ring alkenePlace H and Cl across a trisubstituted ring alkene by comparing the tertiary and secondary cations that protonation could form.
- Protonate an exocyclic double bondChoose the protonation site of an exocyclic alkene so that the resulting ring cation is tertiary, then complete HBr addition.
- Rank two substituted alkene carbonsDecide HBr regiochemistry when both alkene carbons already carry alkyl groups by counting the groups on each possible cation.
- Hydrate a ring alkene at the branch pointPut the hydroxyl group of an acid-catalyzed ring hydration on the methyl-bearing carbon rather than the neighboring ring CH.
- Hydrate styrene through a benzylic cationUse benzylic resonance stabilization to place OH next to the ring during acid-catalyzed hydration of a vinylarene.
- Break a substitution tie with resonancePredict HBr regiochemistry when both alkene carbons carry one substituent, using benzylic resonance rather than a count of alkyl groups.
- Let a carbocation add to a second alkeneApply the Markovnikov cation-stability rule to a carbon electrophile adding to an alkene, then end the sequence by loss of a proton.
- Hydrate an alkene without a free carbocationFollow oxymercuration through a bridged mercurinium ion and choose the carbon that water opens.
- Make an ether without a methyl shiftUse alkoxymercuration to add methanol across an alkene whose carbocation would rearrange, keeping the original carbon skeleton.
- Open a bromonium ion at the tertiary carbonCombine bromonium-opening regiochemistry and anti stereochemistry to draw the trans bromohydrin from a trisubstituted ring alkene.
- Markovnikov addition of HCl to 2-methylpropeneDraw protonation of 2-methylpropene at the CH2 carbon to give the tertiary carbocation, then capture by chloride to give 2-chloro-2-methylpropane.
- Hydroboration–oxidation of 1-methylcyclohexeneDraw hydroboration of 1-methylcyclohexene with boron on the ring CH carbon, then the oxidation sequence that replaces boron with OH to give 2-methylcyclohexan-1-ol.
- Hydroboration–oxidation of 2-methylpent-2-eneDraw the concerted addition of H–B across 2-methylpent-2-ene with boron on the less substituted carbon, then the oxidation (hydroperoxide on boron, alkyl shift to oxygen, borate cleavage, protonation) giving 2-methylpentan-3-ol.
- Alkoxymercuration of 1,2-dihydronaphthalene in methanolDraw alkoxymercuration of 1,2-dihydronaphthalene in methanol: mercurinium ion, methanol attack at the benzylic carbon and demercuration to 1-methoxytetralin.
- Alkoxymercuration of 1-methylcyclohexene in ethanolDraw alkoxymercuration of 1-methylcyclohexene in ethanol: mercurinium ion, ethanol attack at the tertiary carbon, deprotonation and demercuration to 1-ethoxy-1-methylcyclohexane.
- Alkoxymercuration of cyclohexene in methanolDraw alkoxymercuration of cyclohexene in methanol: mercurinium ion, backside methanol attack, deprotonation and demercuration to methoxycyclohexane.
- Alkoxymercuration of methylenecyclopentane in 2-propanolDraw alkoxymercuration of methylenecyclopentane in 2-propanol: mercurinium ion, attack at the ring carbon, deprotonation and demercuration to the tertiary isopropyl ether.
- Alkoxymercuration–demercuration of propeneDraw alkoxymercuration of propene: mercurinium ion, methanol attack at C2, deprotonation, and demercuration to 2-methoxypropane.
- Alkoxymercuration of styrene in methanolDraw alkoxymercuration of styrene in methanol: mercurinium ion, methanol attack at the benzylic carbon, deprotonation and demercuration to (1-methoxyethyl)benzene.
- Oxidize tripropylborane to propan-1-olDraw the oxidation stage of hydroboration–oxidation for one propyl group of tripropylborane: hydroperoxide addition to boron, alkyl migration to oxygen, B–O cleavage and protonation to propan-1-ol.
- DBr + 2-methylpropene labels CH2Draw DBr addition to 2-methylpropene and track where the deuterium label ends up (substrate: 2-methylpropene).
- Ethanol adds to 1-methylcyclohexeneDraw acid-catalysed addition of ethanol to 1-methylcyclohexene: tertiary cation, capture by ethanol and deprotonation to 1-ethoxy-1-methylcyclohexane.
- Ethanol adds to 2-methylpropeneDraw acid-catalysed addition of ethanol to 2-methylpropene: protonation to the tert-butyl cation, capture by ethanol, and deprotonation to the ether (substrate: 2-methylpropene).
- Ethene adds sulfuric acidDraw addition of concentrated sulfuric acid to ethene: protonation of the alkene and capture of the cation by the bisulfate oxygen, giving ethyl hydrogen sulfate.
- HBr Addition to But-1-ene: 2-BromobutaneDraw the electrophilic addition of HBr to but-1-ene: protonation to the secondary carbocation, then bromide capture giving 2-bromobutane.
- HBr Addition to 1-EthylcyclopenteneDraw the electrophilic addition of HBr to 1-ethylcyclopentene: protonation to the tertiary carbocation, then bromide capture giving 1-bromo-1-ethylcyclopentane.
- HBr Addition to 1-MethylcyclohepteneDraw the electrophilic addition of HBr to 1-methylcycloheptene: protonation to the tertiary carbocation, then bromide capture giving 1-bromo-1-methylcycloheptane.
- HBr + 1-methylcyclohexeneDraw protonation of 1-methylcyclohexene at the ring CH and bromide capture of the tertiary cation (substrate: 1-methylcyclohexene, HBr).
- HBr adds to oct-1-eneDraw Markovnikov addition of HBr to oct-1-ene: protonation at C1 to the secondary cation, then bromide capture at C2 (substrate: oct-1-ene).
- HBr + 1-phenylpropeneDraw HBr addition to (E)-1-phenylpropene, where the benzylic cation decides between two secondary carbons (substrate: (E)-1-phenylpropene).
- HBr Addition to 2,3-Dimethylbut-2-eneDraw the electrophilic addition of HBr to 2,3-dimethylbut-2-ene: protonation to the tertiary carbocation, then bromide capture giving 2-bromo-2,3-dimethylbutane.
- HBr Addition to 2-Ethylbut-1-eneDraw the electrophilic addition of HBr to 2-ethylbut-1-ene: protonation to the tertiary carbocation, then bromide capture giving 3-bromo-3-methylpentane.
- HBr + 2-methylpent-2-eneDraw HBr addition to 2-methylpent-2-ene, protonating C3 to place the cation on the dimethyl-substituted carbon (substrate: 2-methylpent-2-ene).
- HBr + pent-2-ene gives two bromidesDraw both competing protonations of (E)-pent-2-ene by HBr and the two bromides they give (substrate: (E)-pent-2-ene).
- HBr Addition to 4-ChlorostyreneDraw the electrophilic addition of HBr to 4-chlorostyrene: protonation to the benzylic carbocation, then bromide capture giving 1-(1-bromoethyl)-4-chlorobenzene.
- HBr adds to allylbenzeneDraw Markovnikov addition of HBr to allylbenzene, where the CH2 spacer keeps the alkene out of conjugation with the ring (substrate: allylbenzene).
- HBr Addition to Cyclohexene: BromocyclohexaneDraw the electrophilic addition of HBr to cyclohexene: protonation to the secondary carbocation, then bromide capture giving bromocyclohexane.
- HBr Addition to EthylidenecyclohexaneDraw the electrophilic addition of HBr to ethylidenecyclohexane: protonation to the tertiary carbocation, then bromide capture giving 1-bromo-1-ethylcyclohexane.
- HBr + methylenecyclohexaneDraw HBr addition to the exocyclic alkene of methylenecyclohexane, protonating the CH2 terminus (substrate: methylenecyclohexane).
- HBr addition to hex-1-ene without peroxidesDraw ionic Markovnikov addition of HBr to hex-1-ene in the absence of peroxides: protonation at C1 to the secondary cation, then bromide capture giving 2-bromohexane.
- HBr without peroxides adds to 1-methylcyclopenteneDraw ionic HBr addition to 1-methylcyclopentene without peroxides: protonation at the ring CH to form the tertiary cation, then bromide capture giving 1-bromo-1-methylcyclopentane.
- HBr without peroxides adds to 2-methylpropeneDraw ionic HBr addition to 2-methylpropene in the absence of peroxides: protonation of the CH2 carbon to form the tert-butyl cation, then bromide capture giving 2-bromo-2-methylpropane.
- HBr without peroxides adds to α-methylstyreneDraw ionic HBr addition to α-methylstyrene without peroxides: protonation at CH2 to form the tertiary benzylic cation, then bromide capture giving 2-bromo-2-phenylpropane.
- HBr with peroxides adds to hex-1-eneDraw the radical chain for HBr/ROOR addition to hex-1-ene: O–O homolysis, H abstraction from HBr, Br· addition at C1 to give the secondary radical, and H transfer giving 1-bromohexane.
- HBr with peroxides adds to 1-methylcyclohexeneDraw the radical chain for HBr addition to 1-methylcyclohexene with a peroxide: initiation, Br· addition at the ring CH carbon to give the tertiary radical, and H abstraction from HBr.
- HBr with peroxides adds to 1-methylcyclopenteneDraw the radical chain for HBr/ROOR addition to 1-methylcyclopentene: initiation, Br· addition at the ring CH to give the tertiary radical, and H abstraction giving 1-bromo-2-methylcyclopentane.
- HBr with peroxides adds to 2-methylpropeneDraw the radical chain for HBr/ROOR addition to 2-methylpropene: initiation, Br· addition at the CH2 carbon to give the tertiary radical, and H abstraction giving 1-bromo-2-methylpropane.
- HBr with peroxides adds to α-methylstyreneDraw the radical chain for HBr/ROOR addition to α-methylstyrene: initiation, Br· addition at CH2 to give the tertiary benzylic radical, and H abstraction giving 1-bromo-2-phenylpropane.
- HBr with peroxides adds to methylenecyclohexaneDraw the radical chain for HBr/ROOR addition to methylenecyclohexane: initiation, Br· addition at the exocyclic CH2 to give the tertiary ring radical, and H abstraction giving (bromomethyl)cyclohexane.
- HBr with peroxides adds to propeneDraw the radical chain for HBr addition to propene with a peroxide: O–O homolysis, H abstraction from HBr, Br· addition at C1, and H abstraction by the secondary radical.
- HBr with peroxides adds to styreneDraw the radical chain for HBr/ROOR addition to styrene: initiation, Br· addition at the terminal CH2 to give the benzylic radical, and H abstraction giving (2-bromoethyl)benzene.
- HBr + propeneDraw the two-step ionic addition of HBr to propene through the secondary carbocation (substrate: propene).
- HBr + styrene via benzylic cationDraw ionic HBr addition to styrene via the resonance-stabilized benzylic cation (substrate: styrene, no peroxide).
- HBr + (E)-but-2-ene gives racemic 2-bromobutaneDraw HBr addition to (E)-but-2-ene and explain why the new stereocentre is racemic (substrate: (E)-but-2-ene).
- HCl + 1,1-diphenyletheneDraw HCl addition to 1,1-diphenylethene through a doubly benzylic tertiary cation (substrate: 1,1-diphenylethene).
- HCl Addition to 1,2-DimethylcyclopenteneDraw the electrophilic addition of HCl to 1,2-dimethylcyclopentene: protonation to the tertiary carbocation, then chloride capture giving 1-chloro-1,2-dimethylcyclopentane.
- HCl Addition to Pent-1-ene: 2-ChloropentaneDraw the electrophilic addition of HCl to pent-1-ene: protonation to the secondary carbocation, then chloride capture giving 2-chloropentane.
- HCl Addition to 1-PhenylcyclohexeneDraw the electrophilic addition of HCl to 1-phenylcyclohexene: protonation to the tertiary benzylic carbocation, then chloride capture giving (1-chlorocyclohexyl)benzene.
- HCl Addition to 2-Methylbut-1-eneDraw the electrophilic addition of HCl to 2-methylbut-1-ene: protonation to the tertiary carbocation, then chloride capture giving 2-chloro-2-methylbutane.
- HCl Addition to 2-Methylbut-2-eneDraw the electrophilic addition of HCl to 2-methylbut-2-ene: protonation to the tertiary carbocation, then chloride capture giving 2-chloro-2-methylbutane.
- HCl Addition to 3-Methylpent-2-eneDraw the electrophilic addition of HCl to 3-methylpent-2-ene: protonation to the tertiary carbocation, then chloride capture giving 3-chloro-3-methylpentane.
- HCl Addition to 4-MethoxystyreneDraw the electrophilic addition of HCl to 4-methoxystyrene: protonation to the benzylic carbocation, then chloride capture giving 1-(1-chloroethyl)-4-methoxybenzene.
- HCl + cyclohexeneDraw HCl addition to the symmetric alkene cyclohexene through a secondary cyclohexyl cation (substrate: cyclohexene).
- HCl Addition to Cyclopentene: ChlorocyclopentaneDraw the electrophilic addition of HCl to cyclopentene: protonation to the secondary carbocation, then chloride capture giving chlorocyclopentane.
- HCl Addition to MethylenecyclopentaneDraw the electrophilic addition of HCl to methylenecyclopentane: protonation to the tertiary carbocation, then chloride capture giving 1-chloro-1-methylcyclopentane.
- HCl Addition to Styrene via a Benzylic CationDraw the electrophilic addition of HCl to styrene: protonation to the benzylic carbocation, then chloride capture giving (1-chloroethyl)benzene.
- HI + hex-1-eneDraw the Markovnikov addition of HI to hex-1-ene through the secondary carbocation (substrate: hex-1-ene).
- HI Addition to 1-MethylcyclohexeneDraw the electrophilic addition of HI to 1-methylcyclohexene: protonation to the tertiary carbocation, then iodide capture giving 1-iodo-1-methylcyclohexane.
- HI Addition to 2-Methylpropene: tert-Butyl IodideDraw the electrophilic addition of HI to 2-methylpropene: protonation to the tertiary carbocation, then iodide capture giving 2-iodo-2-methylpropane (tert-butyl iodide).
- HI Addition to Cyclohexene: IodocyclohexaneDraw the electrophilic addition of HI to cyclohexene: protonation to the secondary carbocation, then iodide capture giving iodocyclohexane.
- HI adds to cyclopenteneDraw protonation of cyclopentene by HI to the cyclopentyl cation and capture of that cation by iodide (substrate: cyclopentene).
- HI Addition to Propene: 2-IodopropaneDraw the electrophilic addition of HI to propene: protonation to the secondary carbocation, then iodide capture giving 2-iodopropane.
- HI Addition to Styrene: (1-Iodoethyl)benzeneDraw the electrophilic addition of HI to styrene: protonation to the benzylic carbocation, then iodide capture giving (1-iodoethyl)benzene. (hydrogen iodide)
- Acid Hydration of 1,2-DimethylcyclohexeneDraw acid-catalysed hydration of 1,2-dimethylcyclohexene: protonation to a tertiary cation, water attack, and deprotonation to 1,2-dimethylcyclohexan-1-ol.
- Hydration of hex-1-eneDraw acid-catalysed hydration of hex-1-ene to the Markovnikov secondary alcohol (substrate: hex-1-ene).
- Acid-catalysed hydration of 1-methylcyclohexeneDraw acid-catalysed hydration of 1-methylcyclohexene: protonation to the tertiary cation, capture by water and deprotonation to 1-methylcyclohexan-1-ol.
- Hydration of 1-methylcyclopenteneDraw acid-catalysed hydration of 1-methylcyclopentene to the tertiary alcohol (substrate: 1-methylcyclopentene).
- Acid-catalysed hydration of 1-phenylcyclopenteneDraw acid-catalysed hydration of 1-phenylcyclopentene: protonation at C2 to the tertiary benzylic cation at C1, water capture and deprotonation.
- Direct tertiary cation, no shiftDraw acid-catalysed hydration of 2,3-dimethylbut-1-ene, where protonation forms a tertiary cation directly (substrate: 2,3-dimethylbut-1-ene).
- Hydration of 2-methylbut-2-eneDraw acid-catalysed hydration of the trisubstituted alkene 2-methylbut-2-ene (substrate: 2-methylbut-2-ene).
- Acid-catalysed hydration of 2-methylpent-1-eneDraw acid-catalysed hydration of 2-methylpent-1-ene: protonation at C1 to the tertiary cation at C2, water capture and deprotonation to 2-methylpentan-2-ol.
- Acid-catalysed hydration of isobutyleneDraw the three-step acid-catalysed hydration of 2-methylpropene: protonation, water attack and deprotonation (substrate: 2-methylpropene).
- Acid-catalysed hydration of α-methylstyreneDraw acid-catalysed hydration of α-methylstyrene: protonation at CH2 to the tertiary benzylic cation, water capture and deprotonation to 2-phenylpropan-2-ol.
- Acid-catalysed hydration of cyclopenteneDraw acid-catalysed hydration of cyclopentene: protonation to the secondary cyclopentyl cation, capture by water and deprotonation to cyclopentanol.
- Industrial hydration of etheneDraw the phosphoric-acid-catalysed hydration of ethene to ethanol (substrate: ethene).
- Acid-catalysed hydration of methylenecyclohexaneDraw acid-catalysed hydration of methylenecyclohexane: protonation of the exocyclic CH2 to the tertiary ring cation, water capture and deprotonation.
- Hydrate methylenecyclopentaneDraw acid-catalysed hydration of methylenecyclopentane: protonation of the exocyclic CH2, water capture of the tertiary cation, and deprotonation (substrate: methylenecyclopentane).
- Acid-catalysed hydration of propene to propan-2-olDraw acid-catalysed hydration of propene with aqueous sulfuric acid: protonation at CH2, water capture of the secondary cation and deprotonation to propan-2-ol.
- Hydration of styreneDraw acid-catalysed hydration of styrene via the benzylic cation to 1-phenylethanol (substrate: styrene).
- Hydroboration–oxidation of but-1-ene to butan-1-olDraw syn hydroboration of but-1-ene by BH3 with boron on C1, then the H2O2/NaOH oxidation that gives butan-1-ol.
- Hydroboration–oxidation of 1-ethylcyclopenteneDraw syn hydroboration of 1-ethylcyclopentene, boron to the ring CH, then hydroperoxide addition, the alkyl shift with retention and release of trans-2-ethylcyclopentan-1-ol.
- Hydroboration–oxidation of hex-1-eneDraw hydroboration of hex-1-ene with boron on the terminal carbon, then the peroxide oxidation that gives hexan-1-ol.
- Hydroboration–oxidation of 1-methylcyclohepteneDraw syn hydroboration of 1-methylcycloheptene with boron on the ring CH carbon, then the peroxide oxidation with retention that gives trans-2-methylcycloheptan-1-ol.
- Hydroboration–oxidation of 1-phenylcyclohexeneDraw syn hydroboration of 1-phenylcyclohexene with boron away from the benzylic carbon, then oxidation with retention to trans-2-phenylcyclohexan-1-ol.
- Hydroboration–oxidation of 2,3-dimethylbut-2-eneDraw syn hydroboration of tetrasubstituted 2,3-dimethylbut-2-ene by BH3 to thexylborane, then the oxidation to 2,3-dimethylbutan-2-ol.
- Hydroboration–oxidation of 2-methylbut-2-eneDraw hydroboration of 2-methylbut-2-ene with boron on the CH carbon, then oxidation to 3-methylbutan-2-ol.
- Hydroboration–oxidation of 2-methylpropeneDraw syn hydroboration of 2-methylpropene by BH3 with boron on the CH2 carbon, then the oxidation that gives 2-methylpropan-1-ol (isobutyl alcohol).
- Hydroboration of 3-methylbut-1-ene without a shiftDraw syn hydroboration of 3-methylbut-1-ene by BH3, then the oxidation to 3-methylbutan-1-ol, showing that no hydride shift occurs.
- 9-BBN hydroboration–oxidation of hex-1-eneDraw hydroboration of hex-1-ene by 9-BBN with boron on C1, then the peroxide oxidation that replaces boron by OH to give hexan-1-ol.
- 9-BBN hydroboration of 3,3-dimethylbut-1-eneDraw hydroboration of 3,3-dimethylbut-1-ene by 9-BBN, then the peroxide oxidation to 3,3-dimethylbutan-1-ol with the carbon skeleton unchanged.
- 9-BBN hydroboration–oxidation of allylbenzeneDraw hydroboration of allylbenzene by 9-BBN with boron on the terminal carbon, then the H2O2/NaOH oxidation to 3-phenylpropan-1-ol.
- 9-BBN hydroboration–oxidation of styreneDraw hydroboration of styrene by 9-BBN with boron on the terminal CH2, then the H2O2/NaOH oxidation to 2-phenylethanol.
- Hydroboration–oxidation of α-methylstyreneDraw syn hydroboration of α-methylstyrene by BH3 with boron on CH2, then the peroxide oxidation to 2-phenylpropan-1-ol.
- BD3 hydroboration–oxidation of 1-methylcyclohexeneDraw syn BD3 addition to 1-methylcyclohexene, then oxidation with retention, placing D cis and the methyl trans to OH in 2-deuterio-2-methylcyclohexan-1-ol.
- BD3 hydroboration–oxidation of 2-methylpropeneDraw BD3 addition to 2-methylpropene, boron to the CH2 and deuterium to the dimethyl-substituted carbon, then oxidation to 2-deuterio-2-methylpropan-1-ol.
- BD3 hydroboration–oxidation of cyclohexeneDraw syn BD3 addition to cyclohexene and the oxidation with retention, showing that deuterium and OH end up cis in 2-deuteriocyclohexan-1-ol.
- BD3 hydroboration–oxidation of propeneDraw hydroboration of propene with BD3, boron to C1 and deuterium to C2, then the peroxide oxidation that gives 2-deuteriopropan-1-ol.
- Hydroboration–oxidation of cyclohexeneDraw syn hydroboration of cyclohexene by BH3, then the peroxide oxidation that replaces boron with OH to give cyclohexanol.
- Hydroboration–oxidation of methylenecyclohexaneDraw hydroboration of methylenecyclohexane with boron on the exocyclic CH2, then oxidation to cyclohexylmethanol.
- Hydroboration–oxidation of propeneDraw hydroboration of propene with boron on C1, then the peroxide oxidation that replaces boron with OH to give propan-1-ol.
- Disiamylborane hydroboration–oxidation of oct-1-eneDraw hydroboration of oct-1-ene by disiamylborane with boron on C1, then the H2O2/NaOH oxidation that gives octan-1-ol.
- Disiamylborane hydroboration of vinylcyclohexaneDraw hydroboration of vinylcyclohexane by disiamylborane with boron on the terminal carbon, then the oxidation to 2-cyclohexylethan-1-ol with no rearrangement.
- Disiamylborane hydroboration of (Z)-4-methylpent-2-eneDraw hydroboration of (Z)-4-methylpent-2-ene by disiamylborane with boron on C2, away from the isopropyl group, then the oxidation to 4-methylpentan-2-ol.
- Hydroboration–oxidation of styreneDraw hydroboration of styrene with boron on the terminal CH2, then oxidation to 2-phenylethanol.
- Methanol adds to 1-methylcyclopenteneDraw acid-catalysed addition of methanol to 1-methylcyclopentene: tertiary cation, capture by methanol and deprotonation to 1-methoxy-1-methylcyclopentane.
- MTBE synthesis from 2-methylpropene and methanolDraw acid-catalysed addition of methanol to 2-methylpropene: protonation to the tert-butyl cation, capture by methanol and deprotonation to MTBE.
- Methanol adds to styrene: (1-methoxyethyl)benzeneDraw acid-catalysed addition of methanol to styrene: protonation to the secondary benzylic cation, capture by methanol and deprotonation to (1-methoxyethyl)benzene.
- Oxymercuration–demercuration of 1-methylcyclohexeneDraw oxymercuration of 1-methylcyclohexene through the mercurinium ion, water attack at the methyl-bearing carbon, deprotonation, and demercuration to 1-methylcyclohexan-1-ol.
- Oxymercuration–demercuration of 1-methylcyclopenteneDraw oxymercuration of 1-methylcyclopentene through the mercurinium ion, water attack at the tertiary carbon, deprotonation and demercuration to 1-methylcyclopentan-1-ol.
- Oxymercuration–demercuration of 1-phenylcyclohexeneDraw oxymercuration of 1-phenylcyclohexene: mercurinium ion, water attack at the benzylic tertiary carbon, deprotonation and demercuration to 1-phenylcyclohexan-1-ol.
- Oxymercuration–demercuration of 4-methoxystyreneDraw oxymercuration of 4-methoxystyrene: mercurinium ion, water attack at the benzylic carbon, deprotonation and demercuration to 1-(4-methoxyphenyl)ethan-1-ol.
- Oxymercuration–demercuration of allylbenzeneDraw oxymercuration of allylbenzene: mercurinium ion, water attack at the internal secondary carbon, deprotonation and demercuration to 1-phenylpropan-2-ol.
- Oxymercuration–demercuration of α-methylstyreneDraw oxymercuration of α-methylstyrene: mercurinium ion, water attack at the tertiary benzylic carbon, deprotonation and demercuration to 2-phenylpropan-2-ol.
- Oxymercuration–demercuration of cyclohexeneDraw oxymercuration of cyclohexene: mercurinium ion, backside water attack, deprotonation and demercuration of the organomercury alcohol to cyclohexanol.
- Oxymercuration of indene to indan-1-olDraw oxymercuration of 1H-indene: mercurinium ion, water attack at the benzylic carbon, deprotonation and demercuration to 2,3-dihydro-1H-inden-1-ol.
- Oxymercuration–demercuration of methylenecyclohexaneDraw oxymercuration of methylenecyclohexane: mercurinium ion, water attack at the ring carbon, deprotonation and demercuration to 1-methylcyclohexan-1-ol.
- Oxymercuration–demercuration of styreneDraw oxymercuration of styrene through the mercurinium ion, water attack at the benzylic carbon, deprotonation and demercuration to 1-phenylethan-1-ol.
- Oxymercuration of vinylcyclohexane without hydride shiftDraw oxymercuration of vinylcyclohexane through the bridged mercurinium ion, water attack at the internal carbon and demercuration to unrearranged 1-cyclohexylethan-1-ol.
Predict the product 5
- Avoid an overextended peroxide ruleLimit the peroxide effect to a supported radical chain.
- Deuterium label in D3O⁺ hydration of 2-methylpropenePredict where deuterium ends up when 2-methylpropene is hydrated in D2SO4/D2O.
- HBr adds to styrenePredict ionic Markovnikov addition of HBr to styrene through a benzylic cation.
- Hydroboration product of 1-methylcyclohexenePredict both regiochemistry and stereochemistry of hydroboration–oxidation on a ring alkene.
- Product table: HBr, H3O⁺ and BH3 on 1-methylcyclopenteneMatch three alkene additions to their products on 1-methylcyclopentene, contrasting Markovnikov and hydroboration orientation.
Classify 3
- Classify two different questionsSeparate connectivity preference from facial preference.
- Classify an alkene by substitutionCount carbon groups on the double-bond carbons to classify an alkene's substitution.
- Which alkene needs an E/Z descriptor?Decide whether an alkene name needs an E/Z descriptor by checking the two groups on each alkene carbon.
Compare 5
- When orientation makes no new productRecognize equivalence of alkene ends by symmetry.
- Rank C4 carbocationsRank carbocations by substitution to predict Markovnikov regiochemistry.
- Rank alkenes by heat of hydrogenationRank alkenes by heat of hydrogenation using substitution and cis strain as stability guides.
- Rank hydrogen halides toward alkenesRelate the rate of HX addition to the acidity of HX.
- Rank alkenes by rate of acid-catalysed hydrationRank alkenes by hydration rate from the stability of the carbocation formed in the slow step.
Calculate 3
- Stability gap from heats of hydrogenationUse heats of hydrogenation to compare the stabilities of isomeric alkenes.
- Equilibrium constant for alkene hydrationConvert a standard free energy of hydration into an equilibrium constant.
- Overall reaction order of HBr addition to an alkeneFind the overall order of HBr addition to an alkene from concentration-doubling data.
Find the error 2
- Catch a misplaced rearrangementDiagnose applying carbocation rearrangement to hydroboration.
- Find the error: bromide attacks the alkene firstIdentify why an arrow from bromide to the C=C bond is wrong in HBr addition to propene.
Interpret the evidence 3
- Follow a deuterium labelTrack atom origin independently of regioselectivity terminology.
- BD3 hydroboration of 1-methylcyclohexene: find DUse a deuterium label to show syn addition and retention in hydroboration–oxidation of 1-methylcyclohexene.
- Rate-determining step of HBr addition to an alkeneUse a rate law to identify the rate-determining step of electrophilic HBr addition.
Work backward 2
- Recover an alkene precursorReverse an unrearranged hydration without changing the skeleton.
- Reverse: alkene behind two methylcyclohexanolsWork backward from a hydration product and a hydroboration product to the single alkene that gives both.
Plan a synthesis 5
- Put oxygen at the endSelect a nonrearranging anti-Markovnikov hydration sequence.
- Make 1-bromo-2-methylpropane from 2-methylpropeneChoose the reagent that converts 2-methylpropene into the primary bromide 1-bromo-2-methylpropane.
- Make 2-methoxy-3,3-dimethylbutane without rearrangementChoose conditions that add methanol to 3,3-dimethylbut-1-ene with Markovnikov orientation and no methyl shift.
- Make the anti-Markovnikov alcoholChoose hydroboration–oxidation to put OH on the less substituted alkene carbon.
- Markovnikov alcohol without rearrangementChoose oxymercuration to add water with Markovnikov regiochemistry while avoiding a carbocation shift.
Explain why 3
- Read a reversible reactionUse reaction quotient reasoning for acid-catalyzed hydration.
- Hammond postulate and HBr addition to propeneUse the Hammond postulate to explain why the more stable carbocation forms faster in HBr addition to propene.
- Why oxymercuration of 3,3-dimethylbutene has no shiftExplain why oxymercuration–demercuration of 3,3-dimethylbut-1-ene gives the unrearranged alcohol.
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