Types of Organic Reactions

– In this subject, we will discuss the general Types of Organic Reactions

Types of Organic Reactions

– Like other compounds, organic molecules undergo acid-base and oxidation-reduction reactions.

– Organic molecules also undergo substitution, elimination, and addition reactions.

(1) Substitution Reactions

– Substitution reaction is a reaction in which an atom or a group of atoms is replaced by another atom or group of atoms.

– In a general substitution reaction, Y replaces Z on a carbon atom.

– Substitution reactions involve σ bonds: one δ bond breaks and another forms at the same carbon atom.

– The most common examples of substitution occur when Z is hydrogen or a heteroatom that is more electronegative than carbon.

Examples of Elimination Reactions

(A) Nucleophilic substitution at an sp³ hybridized carbon atom

(B) Nucleophilic acyl substitution at an sp² hybridized carbon atom

 (C) Radical substitution at an sp³ hybridized C – H bond

(D) Electrophilic aromatic substitution

(2) Elimination Reactions

– Elimination reaction is a reaction in which elements of the starting material are (lost) and a π bond is formed.

– In an elimination reaction, two groups X and Y are removed from a starting material.

– Two σ bonds are broken, and a π bond is formed between adjacent atoms.

– The most common examples of elimination occur when X = H and Y is a heteroatom more electronegative than carbon.

Examples of  Substitution Reactions

β Elimination at an sp³ hybridized carbon atom

(3) Addition Reactions

– Addition reaction is a reaction in which elements are added to a starting material.

– In an addition reaction, new groups X and Y are added to a starting material.

– A π bond is broken and two σ bonds are formed.

– Addition and elimination reactions are exactly opposite.

– A π bond is formed in elimination reactions, whereas a π bond is broken in addition reactions.

Examples of Addition Reactions

(A) Electrophilic addition to carbon-carbon multiple bonds

(B) Nucleophilic addition to carbon-oxygen multiple bonds

Conclusion of general types of reaction in Organic Chemistry

Reference: Organic chemistry / Janice Gorzynski Smith, University of Hawai’i at Manoa / (Third edition), 2011. USA