Chapter 6 - Alkyl Halides: Nucleophilic Substitution and Elimination. In this chapter, we consider the properties and reactions of alkyl halides. After studying this chapter you will be able to: Name alkyl halides, explain their physical properties, and describe their common uses; predict the products of substitution and elimination reactions, and explain what factors favor each type of reaction;. | Chapter 6 Organic Chemistry, 7th Edition L. G. Wade, Jr. Alkyl Halides: Nucleophilic Substitution and Elimination ©2010, Prentice Hall Chapter 6 Classes of Halides Alkyl halides: Halogen, X, is directly bonded to sp3 carbon. Vinyl halides: X is bonded to sp2 carbon of alkene. Aryl halides: X is bonded to sp2 carbon on benzene ring. C C H H H C l vinyl halide C H H H C H H B r alkyl halide I aryl halide Chapter 6 Polarity and Reactivity Halogens are more electronegative than C. Carbon—halogen bond is polar, so carbon has partial positive charge. Carbon can be attacked by a nucleophile. Halogen can leave with the electron pair. Chapter 6 IUPAC Nomenclature Name as haloalkane. Choose the longest carbon chain, even if the halogen is not bonded to any of those C’s. Use lowest possible numbers for position. 3 1 2 4 2-chlorobutane 4-(2-fluoroethyl)heptane 1 2 3 4 5 6 7 1 2 Chapter 6 Examples 1 2 3 4 5 6 7 8 9 6-bromo-2-methylnonane 1 3 . | Chapter 6 Organic Chemistry, 7th Edition L. G. Wade, Jr. Alkyl Halides: Nucleophilic Substitution and Elimination ©2010, Prentice Hall Chapter 6 Classes of Halides Alkyl halides: Halogen, X, is directly bonded to sp3 carbon. Vinyl halides: X is bonded to sp2 carbon of alkene. Aryl halides: X is bonded to sp2 carbon on benzene ring. C C H H H C l vinyl halide C H H H C H H B r alkyl halide I aryl halide Chapter 6 Polarity and Reactivity Halogens are more electronegative than C. Carbon—halogen bond is polar, so carbon has partial positive charge. Carbon can be attacked by a nucleophile. Halogen can leave with the electron pair. Chapter 6 IUPAC Nomenclature Name as haloalkane. Choose the longest carbon chain, even if the halogen is not bonded to any of those C’s. Use lowest possible numbers for position. 3 1 2 4 2-chlorobutane 4-(2-fluoroethyl)heptane 1 2 3 4 5 6 7 1 2 Chapter 6 Examples 1 2 3 4 5 6 7 8 9 6-bromo-2-methylnonane 1 3 cis-1-bromo-3-fluorocyclohexane Chapter 6 Systematic Common Names The alkyl groups is a substituent on halide. Useful only for small alkyl groups. iso-butyl bromide sec-butyl bromide tert-butyl bromide Chapter 6 Common Names of Halides CH2X2 called methylene halide. CHX3 is a haloform. CX4 is carbon tetrahalide. Common halogenated solvents: CH2Cl2 is methylene chloride CHCl3 is chloroform CCl4 is carbon tetrachloride. Chapter 6 Alkyl Halides Classification Methyl halides: halide is attached to a methyl group. Primary alkyl halide: carbon to which halogen is bonded is attached to only one other carbon. Secondary alkyl halide : carbon to which halogen is bonded is attached to two other carbons. Tertiary alkyl halide : carbon to which halogen is bonded is attached to three other carbon. Chapter 6 primary alkyl halide secondary alkyl halide tertiary alkyl halide Primary, Secondary, Tertiary Alkyl Halides * * * 4 Chapter 6 Types of Dihalides Geminal dihalide: two .
