Organic Chemistry, 5th Edition L G. Wade, jr Chapter 5 Stereochemistry Jo blackburn Richland College, Dallas, TX Dallas county community college district C 2003. Prentice hal
Chapter 5 Stereochemistry Jo Blackburn Richland College, Dallas, TX Dallas County Community College District © 2003, Prentice Hall Organic Chemistry, 5th Edition L. G. Wade, Jr
Chirality Handedness: right glove doesnt fit the left hand Mirror-image object is different from the original object > h
Chapter 5 2 Chirality • “Handedness”: right glove doesn’t fit the left hand. • Mirror-image object is different from the original object. =>
Stereoisomers Geometric isomers: cis-trans isomers Enantiomers: nonsuperimposable mirror images, different molecules > tfiltf H H cis-1, 2-dichlorocyclopentane trans-1, 2-dichlorocyclopentane Chapter 5
Chapter 5 3 Stereoisomers • Geometric isomers: cis-trans isomers. • Enantiomers: nonsuperimposable mirror images, different molecules. => cis-1,2-dichlorocyclopentane trans -1,2-dichlorocyclopentane H Cl H Cl H Cl H Cl H Cl Cl H H Cl Cl H
Chiral carbons Tetrahedral carbons with 4 different attached groups are chiral Its mirror image will be a different compound(enantiomer) > mirror Chapter 5
Chapter 5 4 Chiral Carbons • Tetrahedral carbons with 4 different attached groups are chiral. • Its mirror image will be a different compound (enantiomer). =>
Mirror Planes of Symmetry f If two groups are the same, carbon is achiral (animation KH H · A molecule with an internal mirror CI CI plane cannot be Internal mirror plane chiral of symmetry(σ) Caution! If there is no plane of symmetry, molecule may be chiral or achiral. See if mirror image can be superimposed. = Chapter 5
Chapter 5 5 Mirror Planes of Symmetry • If two groups are the same, carbon is achiral. (animation) • A molecule with an internal mirror plane cannot be chiral.* Caution! If there is no plane of symmetry, molecule may be chiral or achiral. See if mirror image can be superimposed. =>