Organic Chemistry 1 Reactions

What happens when an alkene reacts with HX (HCl, HBr, or HI)?

Hydrohalogenation

• Markovnikov addition

• H goes to the less substituted carbon

• X goes to the more substituted carbon

• Carbocation rearrangements are possible

What happens when an alkene reacts with H₂O, H₂SO₄?

Acid-catalyzed hydration

• Produces an alcohol

• Markovnikov addition

• OH goes to the more substituted carbon

• Carbocation rearrangements are possible

What happens when an alkene reacts with:

1. Hg(OAc)₂, H₂O

2. NaBH₄?

Oxymercuration Reduction

• Produces an alcohol

• Markovnikov addition

• OH goes to the more substituted carbon

• No carbocation rearrangements

What happens when an alkene reacts with:

1. BH₃,THF

2. H₂O₂, NaOH

Hydroboration

• Produces an alcohol.

• Anti-Markovnikov addition.

• OH goes to the less substituted carbon.

• Syn addition

What happens when an alkene reacts with OsO₄ and NaHSO_3, H₂O

Dihydroxylation

• Produces two OH groups on adjacent carbons (dashed or wedged)

• Syn addition

• Anti-Markovnikov

What happens when an alkene reacts with H₂ and Pd, Pt, or Ni?

Hydrogenation

• H is added to either side of alkene

• Syn addition

What happens when an alkene reacts with Br₂ or Cl₂?

Halogenation

• Adds two halogens to adjacent carbons

• Anti addition

What happens when an alkene reacts with H₂O or halogen (Br₂ or Cl₂)?

Halohydrin

• Adds Br and OH across the double bond

• OH goes to the more substituted carbon

• Halogen adds to the less substituted carbon

• Anti addition

What happens when an alkene reacts with O₃ followed by DMS

Ozonolysis

• Breaks the C=C double bond

• Produces aldehydes and/or ketones

• Each alkene carbon becomes a carbonyl carbon

What happens when an alkyne reacts with excess H₂ and Pd, Pt, or Ni?

Hydrogenation for Alkynes

• Produces an alkane.

• Triple bond becomes a single bond

What happens when an alkyne reacts with Na° and NH₃(l)

Dissolving Metal Reduction

• Produces a trans alkene

• Triple-bonded carbons become double bonded

What happens when an alkyne reacts with Lindlar's catalyst and H₂?

Lindlar’s Catalyst

• Cis alkene is always produced

• Triple-bonded carbons become double bonded

What happens when an alkyne reacts with Br₂ or Cl₂ and DCM?

Halogenation of Alkynes

• 1 mol: alkene produced with 1 Halogen

• 2 mols: alkane produced with 4 Halogens

What happens when an alkyne reacts with HX?

Hydrohalogenation of Alkyne

• 1 mol: alkene with halogen

• 2 mol: 2 Halogens on the same carbon (more substituted C’s)

What happens when a terminal alkyne reacts with:

1. R₂BH

2. H₂O₂, NaOH?

Hydroboration of Alkynes

• Produces an aldehyde.

• Anti-Markovnikov

• OH goes on the less substituted carbon

What happens when a terminal alkyne reacts with H₂O, H₂SO₄, and HgSO₄?

Oxymercuration (Alkyne Version)

• Produces a methyl ketone.

• Markovnikov

• Enol forms first, then tautomerizes to a ketone.

What happens when an alkyne reacts with O₃ and H₂O?

Ozonolysis of Alkynes.

• Breaks the triple bond

• Produces carboxylic acids

• Terminal carbon is oxidized to CO₂

What happens when an alkane reacts with Cl₂ or Br₂ under hv

Free-Radical Halogenation of an Alkane

• Br goes to the most substituted carbon

• Cl goes to the least substituted carbon

• If chiral, draw enantiomers

What happens when an alkene reacts with HBr and H₂O₂/ROOR (peroxides)?

Radical Addition of HBr to Alkenes

• Anti-Markovnikov addition.

• Br goes to the less substituted carbon

• H goes to the more substituted carbon

What happens when an alkene reacts with NBS and hv?

Allylic Halogenation of Alkenes

• Replaces an allylic hydrogen with Br

• The double bond remains

• Occurs at the carbon adjacent to the double bond

• Uses resonance-stabilized allylic radicals.