CHEM 2370, Chapter 8, Exam 4

Hydrogenation: regiochemistry/rxn type

Syn addition, stereospecific

Hydrogenation: conditions

H2, metal catalyst, pressure

Hydrogenation: products

alkane with an H on either side, syn

Acid Catalyzed Hydration: mechanism

alkene takes an H from catalyst → carbocation rearranges → water attaches to carbocation → catalyst takes an H

Acid Catalyzed Hydration: conditions

catalyst H2SO4 or H3PO4, H2O

Acid Catalyzed Hydration: products

alkene with OH on highest degree outside of where alkene was

Acid Catalyzed Hydration: regiochemistry/rxn type

mark, addition of water, rearrangement possible

Acid Catalyzed Hydration: intermediate

carbocation

Oxymercuration-Demercuration: conditions

Hg2+, THF/H2O, NaBH4, OH-

Oxymercuration-Demercuration: products

alkane with OH on higher degree, H on lower

Oxymercuration-Demercuration: OR- variant

alkane with OR instead of OH

Oxymercuration-Demercuration: regiochemistry/rxn type

mark, addition of water, no rearrangement

Hydroboration-Oxidation: regiochemistry/rxn type

anti-mark, no rearrangement, syn addition, stereospecific

Hydroboration-Oxidation: conditions

BH3, THF, H2O2, OH-

Hydroboration-Oxidation: products

alkane with H on higher degree and OH on lower degree

Ionic Addition: mechanism

alkene takes an H from HBr/ HI on lower degree → carbocation rearranges → Br-/I- attaches to carbocation

Ionic Addition: conditions

HBr or HI

Ionic Addition: products

alkane with Br/I on highest degree carbon outside of where alkene was

Ionic Addition: regiochemistry/rxn type

mark, rearrangement possible

Radical Additions: regiochemistry/rxn type

anti mark

Radical Additions: conditions

HBr/HI and peroxide

Radical Additions: products

Br/I on lower degree, H on higher degree

Halonium Ion: mechanism

alkene takes partially positive Br/Cl to form pseudocarbocation and EN → Br-/Cl- attaches to higher degree partially positive carbon and EN → SN2 like inversion and EN

Halonium Ion: conditions

Br2 or Cl2

Halonium Ion: products

Br/Cl on either side and enantiomer

Halonium Ion: regiochemistry/rxn type

anti-addition, no rearrangement, SN2-like

Halonium Ion: Halohydrin variant

Z (cis) alkene, Br2/Cl2, H2O → Br/Cl on lower degree side and OH on higher degree side and EN

Simmons-Smith Cyclopropane Synthesis: mechanism

alkene and carbene attack each other → cyclopropane

Simmons-Smith Cyclopropane Synthesis: conditions

carbene (CH2 / CR2)

Simmons-Smith Cyclopropane Synthesis: products

syn cyclopropane

Simmons-Smith Cyclopropane Synthesis: regiochemistry/rxn type

syn addition

Simmons-Smith Cyclopropane Synthesis: in-situ carbenes

diiodomethane (CH2I2), Zn(Cn) → cyclopropane

Syn-Dihydroxylation: conditions

Z alkene, OsO4, pyridine, NaHSO3/H2O

or

E alkene, KMnO4, OH-, cold, H2O

Syn-Dihydroxylation: products

OH on either side and enantiomer

Syn-Dihydroxylation: regiochemistry/rxn type

syn additions, no rearrangement

Oxidative Cleavage: conditions

KMnO4, OH-, heat, H3O+

or

O3, CH2Cl2, -78°C, Me2S

Oxidative Cleavage: products

KMnO4 form gives ketones and/or carboxylic acids

Ozone form gives ketones and/or aldehydes

Alkynes: H2, metal catalyst, pressure

hydrogenated all the way to an alkane

Alkynes: H2, Ni2B or P-2

syn addition of H, product is alkene

Alkynes: Lindlar’s Catalyst

syn addition, alkene product

Alkynes: Li or Na, NH3Cl or CH3CH2NH2

anti addition of H, product is alkene

Alkynes: halogenation

X2 + alkyne → anti addition of X on alkene + X2 → second anti addition of X on alkane

Alkynes: hydrohalogenation

alkyne + excess HX → alkene with X and H on opposite sides + EN → alkane with 2 X and 2 H on opposite sides and EN

Alkynes: addition of water, mercury form

alkyne, HG2+, H3O+, H2O → mark enol → ketone

Alkynes: addition of water, boron form

alkyne, BH3, THF, H2O2, OH- → anti-mark enol → aldehyde

alkyne: oxidative cleavage, potassium permanganate form

alkyne, KMnO4, OH-, heat, H3O+ → carboxylic acid + CO2

alkyne: oxidative cleavage, ozone

alkyne, O3, CH2Cl2, -78°C, Me2S → 2 carboxylic acids

Terminal Alkyne Synthesis

viscinal/geminal halide has 2X + excess NaNh2 → alkene with 1X → alkyne → deprotonated alkyne + H3O+ → alkyne

alkyne ion synthesis

NaNH2 takes H from alkyne → alkynide ion

reactions of alkynide ion

good leaving group leaves alkane and deprotonated alkyne attaches in its place

hydrohalogentation intermediate

carbocation

hydroboration with peroxide intermediate

radical

hydration intermediate

carbocation

oxymerc-demerc intermediate

mercurinium ion bridge

hydroboration-oxidation intermediate

hydroxy-boranes

alcohol addition intermediate

carbocation

halogenation intermediate

bromonium ion

bromination in water intermediate

bromonium ion

bromination in alcohol intermediate

bromonium ion

in-situ simmons-smith cyclopropane synthesis intermediate

carbene