Organic Reactions

Organic Reactions

Substitution Reactions

• Involve replacement of a leaving group (LG) with a nucleophile (Nu)
• General equation: R-LG + Nu- → R-Nu + LG
• Types:
  • SN1 (unimolecular nucleophilic substitution): involves formation of a carbocation intermediate
  • SN2 (bimolecular nucleophilic substitution): involves a concerted mechanism with a transition state

Reduction Reactions

• Involve the addition of hydrogen or the removal of oxygen
• General equation: R-X + [H] → R-H + X-H
• Types:
  • Catalytic hydrogenation: uses a metal catalyst to add hydrogen
  • Chemical reduction: uses a reducing agent (e.g. NaBH4, LiAlH4)

Addition Reactions

• Involve the addition of a molecule to a multiple bond (e.g. alkene or alkyne)
• General equation: R-R' + X-Y → R-X-R'-Y
• Types:
  • Electrophilic addition: involves an electrophile (e.g. HCl, Br2)
  • Nucleophilic addition: involves a nucleophile (e.g. water, ammonia)

Oxidation Reactions

• Involve the addition of oxygen or the removal of hydrogen
• General equation: R-H + [O] → R-OH
• Types:
  • Oxidation with oxygen: uses oxygen or an oxidizing agent (e.g. KMnO4, CrO3)
  • Oxidation with halogens: uses a halogen (e.g. Cl2, Br2)

Elimination Reactions

• Involve the removal of a leaving group to form a multiple bond
• General equation: R-X → R=Y + X-H
• Types:
  • E1 (unimolecular elimination): involves a carbocation intermediate
  • E2 (bimolecular elimination): involves a concerted mechanism with a transition state

Organic Reactions

Substitution Reactions

• Leaving group (LG) is replaced with a nucleophile (Nu)
• General equation: R-LG + Nu- → R-Nu + LG
• SN1 (unimolecular nucleophilic substitution): involves a carbocation intermediate, rate-determining step is the formation of the intermediate
• SN2 (bimolecular nucleophilic substitution): involves a concerted mechanism with a transition state, rate-determining step is the formation of the product

Reduction Reactions

• Involve the addition of hydrogen or the removal of oxygen
• General equation: R-X + [H] → R-H + X-H
• Catalytic hydrogenation: uses a metal catalyst to add hydrogen, often uses Pd, Pt, or Ni as catalysts
• Chemical reduction: uses a reducing agent (e.g. NaBH4, LiAlH4), reducing agents can be specific to certain functional groups

Addition Reactions

• Involve the addition of a molecule to a multiple bond (e.g. alkene or alkyne)
• General equation: R-R' + X-Y → R-X-R'-Y
• Electrophilic addition: involves an electrophile (e.g. HCl, Br2), electrophile attacks the π bond
• Nucleophilic addition: involves a nucleophile (e.g. water, ammonia), nucleophile attacks the π bond

Oxidation Reactions

• Involve the addition of oxygen or the removal of hydrogen
• General equation: R-H + [O] → R-OH
• Oxidation with oxygen: uses oxygen or an oxidizing agent (e.g. KMnO4, CrO3), often used to form aldehydes or ketones
• Oxidation with halogens: uses a halogen (e.g. Cl2, Br2), often used to form halohydrins

Elimination Reactions

• Involve the removal of a leaving group to form a multiple bond
• General equation: R-X → R=Y + X-H
• E1 (unimolecular elimination): involves a carbocation intermediate, rate-determining step is the formation of the intermediate
• E2 (bimolecular elimination): involves a concerted mechanism with a transition state, rate-determining step is the formation of the product

Test your knowledge of organic reactions, including substitution and reduction reactions, their types, and mechanisms.