Goc

• Substrate


  It is attacked
• Reagent


  It is the attacking species
• Solvent


  It provides the medium for reaction
• Products


  Outcome of the reaction
• Types of Bond Fission

  • Homolytic
  • Heterolytic
• Nature of bond fission is decided by reagent
• Heterolytic Fission


  Leads to unequal distribution of electrons
• Homolytic Fission


  Leads to equal sharing of electrons
• Factors Affecting Electron Availability

  • Inductive Effect
  • Steric Effects
  • Resonance
  • Aromaticity
  • Conjugation
  • Hyperconjugation
  • Mesomeric Effect
• Inductive Effect


  Permanent polarization transmitted through sigma bonds
• Inductive effect decreases along the carbon chain and is almost negligible after the 4th carbon from functional group</b>
• Inductive effect is additive in nature
• Inductive effect is a weak effect as it is caused by partial transfer of sigma electrons
• Inductive effect of hydrogen is considered as zero
• Electron Donating Group (EDG)


  Groups that have -I effect
• Electron Withdrawing Group (EWG)


  Groups that have +I effect
• Positively charged groups have strong -I effect
• Order of -I effect


  • -NO2 > -CN > -COOH > -F > -Cl > -Br > -I > -C=CH > -O- > -CH=CH2 > -CH3
• • I effect stabilizes negative charge and destabilizes positive charge
• Stability of carbocations


  • 3° > 2° > 1°
• • I effect decreases acidic strength and increases basic strength
• +I effect stabilizes negative charge and destabilizes positive charge</b>
• Order of +I effect

  • 3° > 2° > 1°
• Isotopes with higher mass have stronger +I effect
• Order of +I effect on acidity

  • -CH3 > -CD3 > -CT3
• The decreasing order of stability of alkyl carbonium ions is 3° > 2° > 1° > H
• The correct order of decreasing acid strength is trifluoroacetic acid > trichloroacetic acid > acetic acid > formic acid
• 3


  Alkyl group with 3 carbon atoms
• 4


  Alkyl group with 4 carbon atoms
• +


  Positive charge
• CH3 → C – CH3

  1. Alkyl group with 3 carbon atoms

  2. Carbon atom with 3 alkyl groups attached
• 3°


  Tertiary carbon (3 alkyl groups attached)
• CH3


  Methyl group
• The decreasing order of stability of alkyl carbonium ion is
• Order of stability of alkyl carbonium ions


  • R-C+ > R-C+ > R-C+ > H-C+
• 1. C+ is more stable than R-C+ which is more stable than R-C+ which is more stable than H-C+
• The stability order is: 3° > 2° > 1° > CH3+
• The reason for the stability order is the +I effect and hyperconjugation
• Larger alkyl groups provide greater +I effect and hyperconjugation, increasing stability
• The most stable carbonium ion is the 3° carbonium ion