Chem 334 - Fall 2001
Organic Chemistry I

Dr. Carl C. Wamser

Chapter 5 Notes: Alkene Structure, Elimination Reactions

Alkenes

Unsaturated Compounds

Bonding Trends

Bond Lengths in Angstroms (Bond Strengths in kcal/mole)

 Compound

 Hybrid

 C-C bond

 C-H bond

 ethane

 sp3

 1.54 (88)

 1.11 (98)

 ethylene

 sp2

 1.34 (172)

 1.10 (104)

 acetylene

 sp

 1.21 (230)

 1.08 (125)

Alkene Nomenclature

Cycloalkene Nomenclature

3-methylcyclohexene

5,5-dimethyl-1,3-cyclopentadiene

Alkene Structure

Cis-Trans Isomers

trans-2-butene

cis-2-butene

Cis-Trans Isomers

Stereochemistry Designation

cis or trans ?

E,Z Designation

Priority Rules

Practice Nomenclature

(E)-3,4-dimethyl-2-octene

(Z)

Relative Stabilities

Elimination Reactions - Preparation of Alkenes

Dehydration

Dehydrohalogenation