Organic Chemistry I

Professor Carl C. Wamser

Chapter 5 Notes

Alkene Structure and Preparations

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