Substitution versus Elimination

	Organic Chemistry 4e Carey
	Online Learning Center

Chapter 8: Nucleophilic Substitution

Chapter 8: Nucleophilic Substitution

Substitution and elimination reactions are strongly influenced by many factors. Some of the more important factors are outlined in the following table.
The significance of the effect is stated first, then the system that will favor the reaction is stated.
This should help you deal with the questions....
1. When does an anion function as a Nu and when does it function as a B ?, and therefore,
2. When to I get substitution and when do I get elimination ?

Reaction	Solvent	Nu or Base	Leaving Group	Substrate	Typical Conditions
S_N1	Very Strong Polar solvents	Weak Good Nu and weak base	Strong Good LG	Strong 3^o or resonance stabilized	AgNO₃ / aq. EtOH
S_N2	Strong Polar aprotic solvents	Strong Good Nu and weak base	Strong Good LG	Strong Methyl or 1^o	NaI / Acetone
E1	Very Strong Polar solvents	Weak Weak base	Strong Good LG	Strong 3^o or resonance stabilized	H₂SO₄, heat
E2	Strong Polar aprotic solvents	Strong Poor Nu and strong base	Strong Good LG	Strong 3^o	KOH, heat,

Begin a search: Catalog | Site | Campus Rep

Copyright ©2000 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com.