chemistry fall 2013 course outline

7/29/2019 Chemistry Fall 2013 Course Outline

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Detailed Course OutlineChem 3A; Fall 2013

Subject to change – Revised 9/7/2013

Date Topics Vollhardt text

8/29A IntroductionBond-line notationFunctional groups, R and X notationExamples of some interesting molecules

1.11.92.3

9/3B

Review of bonding ILewis dot structures, ionic and covalent bondingElectronegativity and bond polarizationFormal Charge vs partial charge

1.2-1.4

9/5C

Review of bonding IIResonance structures, including curved arrow notationVSEPR - Molecular shape and bond angles (review/homework – not discussed in lecture) Atomic Orbitals

1.51.3 (last part)1.6

9/10

D

Atomic and Molecular Orbitals

HybridizationSigma bonding and pi bonding Constructing MO diagrams for small molecules

1.7-1.9

9/12E

Introduction to polar reaction mechanismsCurved arrow notation for reactionsDefinitions of acid/base/nucleophile/electrophile/leaving groupPreview of several polar reactions (SN2, SN1, acyl substitution, E2, E1, electrophilic addition toalkenes, acid-catalyzed alkene isomerization, nucleophilic addition to ketones)Kinetics, thermodynamics, and reaction coordinate diagramsAcid/base reactions: equilibrium and energy

2.1-2.2

9/17F

Acidity, Basicity, and StructureDefinitions of Ka/pKaTrends affecting pKa (electronegativity, charge, hybridization, size, resonance, inductive effects)

2.2, 8.3

9/19G

NomenclatureConstitutional isomerismBasics of IUPAC nomenclatureBase chain names (prefixes for 1-10 carbons); common names of branched substituents

Naming alkenes, alkynes, haloalkanes, alcohols, ethers, and amines Alkane conformational analysisSingle bond rotation in acyclic alkanes

Newman projections, wedge-dash notation, Fisher projectionsequilibrium and free energy (“1.36 rule” at room temp)

2.42.5, 4.1

2.7-2.8

9/24H

Alkane conformational analysis (finish discussion from prev. lecture) CycloalkanesRing strain, combustion analysis of alkanesChair cyclohexane (ring flipping, axial and equatorial)Stereoisomerism (cis/trans) in cyclic systems

2.7-2.8

4.24.34.4

9/26I

Stereochemistry IChiralityOptical activityR/S nomenclature

5.15.25.3

10/1J

Stereochemistry IIE/Z nomenclature for alkenes, alkene stereoisomerismAxial chiralityMutiple stereocenters (diastereomers, meso)Resolution of enantiomers

11.1

5.5, 5.65.8



10/3K

Overview of Nucleophilic Substitution (S N2 and S N1)“nucleophile”, “electrophile”, “leaving group”Curved arrow notationKinetics, rate laws, reaction coordinate diagramsStereochemistry, orbital pictures

6.26.36.46.5

10/7 Midterm Exam #1 – 7pm ----

10/8L Factors that Affect S N2 ReactivityLeaving group abilitySterics

Nucleophile strength, reversibility of S N2 reactions, solvation

6.76.96.8

10/10M

Some specific S N2 examplesAlcohol as an electrophile: preparation of haloalkanes from alcohols: HX, PBr 3, SOCl 2 Alcohol as a nucleophile: Preparation of ethers, cyclic ethers including epoxidesAlcohols from S N2 reaction of epoxides with good nucleophilesS-Adenosylmethionine – nature’s alkylating reagent

9.2, 9.49.69.9

10/15 N

E2 reactionsCompetition between substitution and elimination (base strength, steric effects)Reactive conformations and stereochemical consequencesOrbital description of reactionKinetic control of product ratio (irreversible reaction)E2 reactions of dihaloalkanes to form alkynes

7.77.8

11.613.4

10/17O

SN1 reactionsSolvolysis – includes proton transfer step(s)Reaction coordinate diagrams, kineticsCarbocation substitution and stability – hyperconjugationEffects of solvent, leaving group, competing nucleophilesStereochemistry of SN1, ion pairing and its effect on stereochemistryReactions of epoxides under acidic conditions

7.1-7.5

9.910/22P

E1 reaction; Addition to alkenes in acidE1 reaction overview, competition between SN1 and E1Reversibility of the E1 reaction, LeChatelier’s principle:

-Use of Ag salts with haloalkanes; addition of HX to alkenes-Dehydration of alcohols, hydration of alkenes

Alkene isomerization in acidic conditions, alkene stability trendsThermodynamic vs. kinetic control of alkene product ratiosCarbocation rearrangements (hydride shift, alkyl shift)

7.6

xx, 12.39.2,11.7, 12.4

9.3

10/24Q

Summary/Review (SN2/E2/SN1/E1)- effects of alkyl substitution/branching, solvation, base strength- reversibility, choice of reaction conditions to control product outcome- stereocontrol (concerted vs stepwise reactions); synthetic utility

7.9

10/29R

Reactions of alkenes I - reactions with carbocation intermediatesAlkene oligomerization/polymerization under acidic conditionsAddition of HX or H 2O to alkynes under acidic conditionsSubstitution of allylic halides – resonance stabilization of carbocation polyalkenes in nature(polymerization and cyclization examples)

12.1413.714.314.10

10/31

S

Reactions of alkenes II – 3-membered rings

Addition of Br 2 to alkenes – anti addition, bromonium ion intermediateAddition of other nucleophiles to bromonium ion intermediateEpoxidation of alkenes with mCPBAComparison of bromonium ion reactivity to protonated epoxide reactivitycyclopropanation of alkenes (diazomethane, chloroform, Simmons-Smith reagent)Addition of Br 2 to alkynes

12.512.612.10

12.913.7

11/5T

Reactions of alkenes IIIHydroboration/oxidation of alkenes and alkynesDihydroxylation (OsO 4, H 2O2)

12.8, 13.812.11



Ozonolysis (O 3, then Me 2S)Hydrogenation of alkenes (H 2, Pd/C)

12.1212.2

11/7U

Multistep Synthesis I Interconversion between alkenes, alcohols, and haloalkanesComparison of alcohol synthesis methods – regioselectivity, stereoselectivity, and syntheticutility

11/12V Oxidation and ReductionDefinitions of oxidation and reduction in the context of organic compounds – application of definitions to reactions already discussed.Oxidation of alcohols to carbonyls (CrO 3, PCC) – focus on elimination step (compare to E2reaction)Overview of reduction of alcohols by NaBH 4 or LiAlH 4

NAD+ and NADH for oxidations and reductions in biological systems (see pages 298 and 1186)

8.6

11/12 Midterm Exam #2 – 7 pm ----11/14W

Addition of nucleophiles to aldehydes and ketonesComparison of alkene pi bond to carbonyl pi bond – the effect of a strong bond dipole.Details about metal hydrides reductions, compare/contrast with alkene hydrogenationGrignard, and organolithium reagents – synthesis, basicity, addition toketones/aldehydes/epoxides (but not SN2 of haloalkanes)Alkynyl anion as a nucleophile

8.7

13.511/19X

Multistep Synthesis II Utility of carbon nucleophiles to build complexity, oxidation of alcohols as a key stepProtecting groups as a synthetic strategy (tert-buyl ether, silyl ether protection of alcohols duringGrignard reactions)

8.8, 8.99.8

11/21Y

Reactions with radical intermediates IHomolytic cleavage of bonds, curved arrow notationStructure and stability trends of radicals, BDEs

pyrolysis of alkaneshalogenation of alkanes – radical chain mechanism

3.13.23.33.4-3.5

11/26Z

Reactions with radical intermediates IIRadical halogenation of alkanes – selectivityRadical allylic halogenation – resonance stabilization of the radical intermediateRadical-mediated addition of HBr to alkenes and alkynesRadical initiators: peroxides, AIBN

3.6-3.814.212.13,13.8

11/28 Thanksgiving break ---12/3AA

Reactions with radical intermediates IIIRadical polymerization of alkenesDissolving metal reduction of alkynesRadicals in biological systems

12.1513.6

12/5AB

Multistep Synthesis IIIreview for final exam

chemistry fall 2013 course outline

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