Lecture Slides • Spring 2012

Lecture 1: January 10, 2012
Lecture 1: January 10, 2012
Main topics include:
• Syllabus
• i>clicker & OWL registration
• website
• define organic chemistry
• orbitals (Schrodinger equation)
• valence electrons
• models of bonding
• bond-line formulas
The following slides were presented during lecture on the dates indicated. These slides are only made available after the indicated lecture date. Every effort is made to correct errors found on slides during lecture before posting. i>Clicker questions may also be found within the slides in the order they were presented during lecture. Alternatively, i>clicker questions, correct answers and statistics can be found on the i>clicker page.

Lecture 2: January 12, 2012
Lecture 2: January 12, 2012
Main topics include:
• electron configuration
• formal charge
• VSEPR
• resonance
• curved arrow notation
• structural effects on acid strength
• electronegativity (periods)
• bond strength (groups)
• resonance
Lecture 3: January 17, 2011
Lecture 3: January 17, 2012
Main topics include:
• acidity/pKa
• classes of hydrocarbons
• alkanes/valence bond model
• sp3 hybridization/sigma bonds
• nomenclature of alkanes/cycloalkanes
• physical properties of alkanes
• van der Waals forces (London disp.)
• chemical properties/acidity of alkanes
• combustion/redox on carbon
Lecture 4: January 19, 2012
Lecture 4: January 19, 2012
Main topics include:
• isomers classification
• conformations of alkanes
• drawing conformations: Newman projections, sawhorse, dash & wedge
• steric vs. hyperconjugation argument
• heats of combustion of cycloalkanes
• conformations of cyclopropane, cyclobutane, and cyclopentane
• summary of strain types
Lecture 5: January 24, 2012
Lecture 5: January 24, 2012
Main topics include:
• quantitative energy costs for various conformational relationships
• chair & boat conformations for cyclohexane (axial & equatorial bonds)
• mechanism of ring inversion
• drawing cyclohexane rings
• conformational analysis for mono and disubstituted cyclohexanes (1,3-diaxial)
Lecture 6: January 26, 2012
Lecture 6: January 26, 2012
Main topics include:
• equilibrium and free energy
• configurational vs. constitutional
• functional groups
• naming alcohols and alkyl halides
• physical properties of alcohols
• physical properties of alkyl halides
• preparation of alkyl halides
• reactivity
• alternative conditions & reagents
Lecture 7: January 31, 2012
Lecture 7: January 31, 2012
Main topics include:
• Exam 1 info
• mechanisms: SN1, SN2
• carbocations
• inductive effect & hyperconjugation
• transition states
• rate laws for rate determining step
• halogenation of alkanes
• selectivity of halogenation
• Hammond Postulate
Lecture 8: February 2, 2012
Lecture 8: February 2, 2012
Main topics include:
• alkenes/olefins
• IHD review
• alkene/alkenol nomenclature
• structure/bonding of double bonds
• barrier to rotation
• geometrical isomers: cis & trans
• CIP rules for prioritizing groups
• B-eliminations introduction; dehyd.
Lecture 9: February 7, 2011
Lecture 9: February 7, 2012
Main topics include:
• dehydration regioselectivity (Zaitsev)
• dehydration stereoselectivity
• E1 & E2 mechanisms
• rearrangements
• dehydrohalogenation
• conditions/alkoxides
• E2 mechanism (anti elimination)
• anti E2 (molecular orbital argument)
• anti E2 (conformational argument)
CHEM 232 Lecture: February 12, 2012
Lecture 10: February 9, 2012
Main topics include:
• addition reactions to alkenes
• hydrogenation: conditions, syn add.
• heat of hydrogenation
• Markovnikov addition of HX
• mechanistic explanation for Mark.
• peroxide effect on HBr addition
• H2SO4 and H2O addition
• microscopic reversibility
• intro to synthesis
Lecture 11: February 14, 2012
Lecture 11: February 14, 2012
Main topics include:
• hydroboration-oxidation (
syn add.)
• regioselectivity of and mechanism
• halide addition to alkenes
• stereoselectivity of halide add. (
anti addition; halohydrins & regioselect.)
• epoxidation
• ozonolysis
• synthesis; retrosynthesis
Lecture 12: February 16, 2012
Lecture 12: February 16, 2012
Main topics include:
• mirror images
• chirality: chiral objects
• chirality center: chiral molecules
• pyramidal inversion: N, S, P
• achiral test: plane of symmetry
• achiral test: center of symmetry
• R/S notation based on CIP rules
• optical isomers: enantiomers
• stereogenic vs. chirality center
Lecture 13: February 13, 2012
Lecture 13: February 21, 2012
Main topics include:
• IUPAC nomenclature of stereoisomers
• drawing Fisher projections
• properties of enantiomers
• optical rotation (enantiomeric excess)
• diastereomers & meso forms
• determining # of stereoisomers
• reactions that create chirality center
• stereospecific vs. stereoselective
Lecture 14: February 23, 2012
Lecture 14: February 23, 2012
Main topics include:
• nucleophilic substitution
• nucleophiles & electrophiles
• reactivity of halide leaving groups
• review: SN2 of alcohols by halides
• SN2 mechanism
• inversion of configuration
• backside attack (molecular orbitals)
• stereospecific SN2 reactions
• steric effects & nucleophilicity
Lecture 15: February 28, 2012
Lecture 15: February 28, 2012
Main topics include:
• non-nucleophilic bases
• SN1 mechanism
• solvolysis
• carbocation stability (review)
• rate of SN1 & SN2: solvent effects
• stereochemistry of SN1
• Elimination-Substitution competition
• conditions favoring substitution
• Alkyl sulfonates as leaving groups
Lecture 16: March 1, 2012
Lecture 16: March 1, 2012
Main topics include:
• Substitution/Elimination review
• alkynes: nomenclature
• structure of alkynes, review
• bonding/hybridization, review
• terminal alkynes as acids
• commonly encountered bases
• alkylation of alkyne carbanions
• dialkylation
• limitation: only applies to methyl & 1º
CHEM 232 Lecture 17: October 20, 2011
Lecture 17: March 6, 2012
Main topics include:
• alkyne alkylation review
• retrosynthetic strategies: alkynes
• double dehydrohalogenation
• hydrogenation of alkynes
• Lindlar Pd
• metal-ammonia reduction
• Hg cat. hydration
• addition of halogens
• hydroboration/oxidation of alkynes
CHEM 232 Lecture: Oct. 27, 2011
Lecture 18: March 8, 2012
Main topics include:
• allylic carbocation and radicals
• allylic SN1: stabilization of carbocat.
• allylic SN2: steric hind. & MO model
• rate of allylic SN2
• allylic halogenation: mechanism
• allylic halogenation in synthesis
• NBS
• delocalization energy
• conform. analysis (s-Cis, s-Trans)
• allenes & chirality
CHEM 232 Lecture 19: November 1, 2011
Lecture 19: March 13, 2012
Main topics include:
• prep. of dienes (elimination rxns)
• addition of HX to conjugated dienes
• thermodynamic/kinetic control
• Diels-Alder, stereospecificity
• Diels-Alder, activating groups
• FMO theory applied to Diels-Alder
• drawing MO diagrams
• electronic effects on HOMO/LUMO
CHEM 232 Lecture 20: October 28, 2010
Lecture 20: March 15, 2012
Main topics include:
• symmetry-allowed cycloadditions
• regioselectivity of Diels-Alder
• sterespecificity of Diels-Alder
Endo selectivity for EWGs
• Out-Endo-Cis rule
• Arenes & aromaticity (Kekule)
• resonance energy
π-MOs of benzene vs. 1,3,5-hexatriene
• nomenclature
CHEM 232 Lecture 21: March 27, 2012
Lecture 21: March 27, 2012
Main topics include:
• aromatic effects on structure & reactivity (e.g. acidity)
• Hükel's Rule: aromatic, antiaromatic
• Frost Circles
• Heterocylic aromatic compounds
• benzylic free radical halogenation
• benzylic SN1 & SN2 (MOs)
• preparation of alkenylbenzenes
• regioselectivity AdE to alkenylbenznes
CHEM 232 Lecture 22: March 29, 2012
Lecture 22: March 29, 2012
Main topics include:
• AdE to alkenes: review
• Electrophilic aromatic substitution
• Formation of SEAr electrophiles
• Rate of SEAr: Effect of EDGs & EWGs
• Regioselectivity of SEAr

CHEM 232 Lecture 23: April 3, 2012
Lecture 23: April 3, 2012
Main topics include:
• SEAr i>Clicker review
• Rate of SEAr: Effect of EDGs & EWGs
• Regioselectivity of SEAr
• Ortho/Para; meta directors
• classification of activating effects
• degree of electron donations
• multiple substituent effects
• SEAr in synthesis: order matters!
CHEM 232 Lecture: April 5, 2012
Lecture 24: April 5, 2012
Main topics include:
• Review: Redox on carbon
• Hydride donors/reductions
• Mechanism of hydride reductions
• Reactivity of esters vs. ketones
• Reactivity of NaBH4 vs. LiAlH4
• Diols
• Dihydroxylation
• Sharpless enantioselective dihydroxy.
• Formation of ethers from diols
CHEM 232 Lecture 25: April 10, 2012
Lecture 25: April 10, 2012
Main topics include:
• Intramolecular Williamson
• Fisher esterification (pattern only)
• Dean-Stark trap
• Acylation of alcohols
• Oxidation of Alchols (chromic acid)
• [O] of Alcohols (Swern & Dess-Martin)
• NAD+ oxidation
• Oxidative cleavage of vicinal diols
CHEM 232 Lecture 26: April 12, 2012
Lecture 26: April 12, 2012
Main topics include:
• Ethers, sulfides nomenclature
• Structure and bonding
• Conformational analysis of oxanes and thianes, A-values
• Physical properties of ethers
• Crown ethers, nucleophilicity
• Preparation of ethers
• Williamson ether synthesis
• Cleavage of ethers
CHEM 232 Lecture 27: April 24, 2012
Lecture 27: December 1, 2011
Main topics include:
• Chauncey sings. . .
• Epoxidation by peroxy acids
• Sharpless Enantioselective Epoxid.
• Epoxides by Intramolec. Williamson
• Anionic Ring Opening of Epoxides
• Acid-cat. Ring Opening of Epoxides
• Dihydroxylation strategies
• Preparation of Sulfides, alkylation
• Sulfoniums, S-adenosylmethionine
• Chauncey signs one last time. . .
CHEM 232 Lecture 28: November 29, 2010
Lecture 28: November XX, 201X
Main topics include:
CHEM 232 Lecture 29: December 2, 2010
Lecture 29: December X, 201X
Main topics include: