Chemistry 220--Fall, 2007
Topic Outline
In general the course will be organized in the same order as the coverage of topics in the textbook, Introduction to Organic Chemistry, 3rd Ed., by W. H. Brown and T. Poon (John Wiley & Sons). Material from Chap 11 and 12 will not be covered in the lecture, but some of the topics from those chapters will be included in the lab.
Chap 1. Covalent Bonding and the Shapes of Molecules: A review of basic concepts including the structure of atoms, ionic bonding, covalent bonding and shapes of molecules (VSEPR model), polar and nonpolar molecules, formal charge, resonance, hybrid orbitals, and functional groups.
Chap 2. Acids and Bases: Arrhenius acids and bases, Brĝnsted-Lowry acids and bases. Acidity constant pKa and acid-base equilibria. Relationships between structure and acidity (inductive and resonance effects). Lewis acids and bases.
Chap 3. Alkanes and Cycloalkanes: "Saturated" "aliphatic" hydrocarbons. Structure and bonding in alkanes. Tetrahedral geometry of carbons in alkanes, bond angles and shapes of molecules. General carbon-hydrogen ratio in acyclic alkanes. Constitutional isomerism in alkanes. Nomenclature of alkanes; the IUPAC system. Alkyl group names derived from names of alkanes. Common names of alkanes. Classification of carbon and hydrogen atoms in alkanes as primary (1o), secondary (2o), tertiary (3o), and quaternary (4o). Cycloalkanes, structure, pictoral representations, line-angle drawings, naming cycloalkanes. Application of IUPAC nomenclature to "unsaturated" hydrocarbons and members of some other functional group families. Rotation about carbon-carbon single bonds, conformations of alkanes and cycloalkanes; Newman projections. Staggered and eclipsed conformations of ethane. "Chair" and "boat" conformations of the six-membered ring in cyclohexane. Equatorial and axial bonds in the chair conformation. Cis-trans isomerism in substituted cycloalkanes. Physical properties of alkanes; nature of intermolecular forces (dispersion forces) and effect on boiling points. Effect of increasing chain length and degree of branching on boiling points of alkanes. Combustion of alkanes. Sources of alkanes (natural gas, petroleum, coal).
Chap 4. Alkenes and Alkynes: "Unsaturated" hydrocarbons: alkenes, alkynes, arenes. Phenyl groups and other aryl groups. Vinyl and allyl groups. Shapes of alkenes, sp2 hybridized carbon, trigonal planar geometry. Nature of the double bond: sigma (s) bonds and pi (p) bonds. Restricted rotation around the double bond in alkenes; cis-trans isomerism in some alkenes. Shapes of alkynes, 180o bond angles around sp hybridized carbon atoms. IUPAC nomenclature of alkenes and alkynes. Common names of some important simple alkenes and alkynes. The E,Z system for specifying stereoisomerism around a double bond. Naming cycloalkenes. Compounds with more than one double bond: dienes, trienes, polyenes. Physical properties of alkenes and alkynes. Naturally-occurring alkenes: terpenes and the isoprene rule.
Chap 5. Reactions of Alkenes: Examples of addition reactions. Basic concepts of "reaction mechanisms"; energy diagrams and transition states. Activation energy (Ea) and heat of reaction (DH) for a reaction. "Electrophiles" and mechanism of electrophilic addition to the carbon-carbon double bond of an alkene. Carbocations as intermediates, relative stability of tertiary (3o), secondary (2o), primary (1o), and methyl carbocations. Markovnikov's rule for addition to unsymmetrically substituted double bonds. Addition of hydrogen halide to a double bond. Acid-catalyzed hydration of double bond. Halogenation of double bond (bridged halonium ion intermediate and "anti" addition). Oxidation and reduction of hydrocarbons. Oxidation of alkenes: formation of glycols, "syn" addition in the osmylation of alkenes. Catalytic reduction of alkenes to alkanes (hydrogenation). Heats of hydrogenation as a measure of alkene stability. Reactions which produce chiral compounds.
Chap 6 Chirality: Stereoisomerism, chirality, enantiomers and diastereomers. Recognizing chiral and achiral molecules, identifying "stereocenters." The R,S system for designating "configuration" at a stereocenter. Acyclic molecules with two or more stereocenters, enantiomers and diastereomers; meso compounds, cyclic compounds with two stereocenters. Properties of a pair of enantiomers; properties of diastereomers. Optical activity and chirality; polarimetry and rotation of the plane of polarization of plane-polarized light; dextrorotatory and levorotatory compounds. Racemic mixtures and resolution of racemates. Chirality in biomolecules, chiral recognition in nature. Biochemically, it's a chiral world.
Chap 7 Haloalkanes: Nomenclature by IUPAC system. Common names of some important haloalkanes (also called alkyl halides). "Nucleophiles" and nucleophilic aliphatic substitution reactions of haloalkanes. Mechanisms of nucleophilic aliphatic substitution: bimolecular (SN2) and unimolecular (SN1) mechanisms; stereochemistry, reactivity, potential energy diagrams, structure of alky halide, strength of nucleophile, leaving group ability of halide. Elimination of elements of a hydrogen halide from an alkyl halide to give an alkene; Zaitsev's rule. Mechanisms of elimination: bimolecular (E2) and unimolecular (E1).
Chap 8 Alcohols, Ethers, and Thiols: Structure and nomenclature of alcohols, IUPAC and common names. Classification of alcohols as tertiary (3o), secondary (2o), primary (1o). Ethers, structure and nomenclature. Physical properties of alcohols: intermolecular attraction (hydrogen bonding) associated with the high polarity of the OH bond; comparison of boiling points of alcohols with boiling points of hydrocarbons of comparable molecular weight. Intermolecular attraction between ether molecules (weak dipole-dipole attraction); comparison of boiling points of isomeric alcohols and ethers. Thiols and thioethers. Acidity of the OH bond in alcohols (comparison with water). Basicity of alcohols, protonation of the oxygen atom by strong acids. Formation of alkoxide salts by reaction of alcohols with alkali metals (Na, K, Li). Conversion of alcohols to alkyl halides, SN1 substitution for 2o and 3o alcohols; SN2 substitution for 1o alcohols and methanol. Acid-catalyzed dehydration to give alkenes (Zaitsev's rule) mechanism. Oxidation of 1o and 2o alcohols. Reactions of ethers. Epoxides: synthesis and ring-opening reactions.
Chap 9 Benzene and Its Derivatives: Aromatic compounds (arenes), structure and unusual stability of benzene; Kekulé model, valence bond model, resonance model; the six-electron cyclic p electron cloud and resonance energy. Criteria for aromaticity: Hückel's rules for aromaticity. Heterocyclic aromatic compounds. Nomenclature of substituted benzenes. Polynuclear aromatic hydrocarbons (PAHs). Phenols (hydroxybenzenes): acidity and electron-delocalization. Alkylbenzenes: oxidation at the "benzylic" position. Electrophilic aromatic substitution: general mechanism. Halogenation, nitration, sulfonation, alkylation and acylation of benzene--mechanisms. Disubstituted benzenes: effects of one substituent on further substitution on the aromatic ring. Ortho-para directing groups; meta directing groups. Activating groups and deactivating groups.
Chap 10 Amines: Structure and classification of amines; relationship to ammonia. Nomenclature and physical properties. Basicity of amines, electron-delocalization and basicity of arylamines. Reaction of amines with acids.
Spectroscopy (Chap 11 and 12) will not be covered in lecture.
Chap 13. Aldehydes and Ketones: The nature of the carbonyl group. Structure and bonding in aldehydes and ketones. IUPAC nomenclature of aldehydes and ketones; common names of some important aldehydes and ketones. Physical properties. Addition of nucleophilic reagents to the carbonyl group. Addition of Grignard reagents (organomagnesium halides) to carbonyl groups--a versatile synthesis of alcohols. Addition of alcohols to carbonyl groups--hemiacetals and acetals. Addition of nitrogen nucleophiles to carbonyl groups. Reactivity at the carbon adjacent to the carbonyl carbon in an aldehyde or ketone (called the a-carbon). Keto-enol tautomerism; enolizable carbonyl compounds. Oxidation of aldehydes to carboxylic acids. Reduction of aldehydes to 1o alcohols or ketones to 2o alcohols. Metal hydride reducing agents.
Chap 14. Carboxylic Acids: Nature of the carboxyl group. IUPAC nomenclature; common names of some important carboxylic acids. Physical properties: hydrogen bonding dimers. Hydrophilic and hydrophobic groups and effect of length of carbon chain on solubility in water. Ka and pKa values: effect of substituents on acidity of carboxyl group. Reaction with bases, formation of salts. Reduction of carboxyl group to a 1o alcohol. Esterification of carboxylic acids (Fischer esterification). Conversion of carboxylic acids to acid halides (acyl halides). Decarboxylation of b-ketoacids and of malonic acid derivatives.
Chap 15. Functional Derivatives of Carboxylic Acids: Structure and nomenclature of acid halides, acid anhydrides, esters, and amides. Nucleophilic acyl substitution reactions: hydrolysis, reaction of acid halides and anhydrides with alcohols to give esters; reaction of acid halides, anhydride, and esters with amines to give amides. Reaction of esters with Grignard reagents. Reduction of esters to alcohols and of amides to amines.
Chap 16. Enolate Anions: Formation of enolate anions. Reactions of enolate anions: Aldol reactions, Claisen and Dieckmann condensations, mechanisms. Biological versions of Claisen and aldol condensations.
Chap 17. Polymers: Monomers and polymers, repeat units. Thermoplastic and thermosetting plastics. Polyesters, polyamides, polyurethanes, epoxy resins (Step-growth polymers). Chain-growth polymers: polyethylene and related free radical polymers.
Important Classes of Biomolecules (selected topics from Chap 18, 19, 20, 21, and 22 as time allows): A brief overview of the structures of carbohydrates, lipids, proteins, and nucleic acids, and an introduction to metabolism of fats and carbohydrates.