Language,Mechanism and selectvitiy in organic reaction -8stereochemistry and conformational analysis -12Pericycle Processes-8Aromatic Chemistry-8Hetroaromatic Chemistry-10Organometallic Chemistry -32Synthetic Chemistry of C=O group and redox Chemistry-15Retrosynthesis-17
SubstitutionNucleophilic sub and electrophilic sub
EliminationHoffman EliminationAdditionA diels Alder cycloaddtionMarkovnikov additionRearrangementBeckmann Rearrangement
Slide 6
Klopman-Salem (3 parametres)
Filled oribtals-filled oribtal - always postive and replusion
Filled-unfilled oribtals-Sharing and stablizing (-ve) reduces Ea
Electrostatic -like-unlike-stablizing
destablizing when like-like
Slide 7
Electronic effects-(Energy=Reacti)
The Inductive effect-Polarization that a polar bond induces into other parts of the molecules through a sigma bond framework which affect electron density within the molecule.General rules:(I+)Electron released to a postive charge ,reduces Energy.(I-) Electrons released to a negative charge,raise Energy.(I+)Electrons released to - charge ,Raise energy.(I-) Electrons withdrawl ,reduce energy .
Slide 8
Electronic effects -Continued...
The more charge on a atom-the more destabilize it will beThe less charge on a atom- the more stablized it will be .Acidicity and Basicity(I+)- effect attached to molecule-,increases the overall electron density on the molecule and the molecule is able to donate it elctrons= Basic(I-) effect atached to the molcule ,decrease the overall electron density on the molecule,making it electron defiicient .Therefore increasing it acidity .
Measure of how strong a acid is by the stablization of the conjucated base.How willing is your acid to give up it proton.?
Slide 10
4 factors
Electronnegativity - The charge on a en atomincrease across the pt and up the groupHow willing is the element to accept the electronmore willing-stable,less willing destableResnance-Deloclization of charge over a number of atoms .Spreading the charge helps to stablize it.Induction -The pulling of electrons
Slide 11
Field effect
Stereiosmers -Replusion between atoms raise the complex in energy,more unstable conj base=weaker acid.
Operates through spaces or solvent molcules not bonds.Take the geometry into account.The inductive effect of the cl atoms on the position of the electrons in the COOH group , differ as cl are closer in space in 1 than 2 .Filed effects are more important than inductive effects.
Associated with the delocalistaion of electrons affecting electron distribution.Involes sigma-Hyper conjucationpi electronsCanonical formThe real structure is a hybird of all the canonical forms and is lower in energy than resonance form.All atoms taking part in resonance must lie in plane or neraly so to ensure good overlap between oribtals.
Slide 14
Generation of resonace structures
ELECTRONS MUST BE SHIFTED!!!!!!!!!!!Electron releasing group =pi system= Push 1 lone pair from each group into pi system(n-pi)Electrn withdrawing group=pi-pi= pull pi electrons into group .For unsubstituted systems:Benzene1,3butdiaene seperate pi bond into a +ve and -ve way
Add to the site which will give the most stable compound, i.e lower in energy.
Carbanions can be rationalized in the same way.
Their energy increases with electron being released and decrease with electrons be removed.
Slide 16
Stereoelectronic Effects
Where a structural or reaction sitution involves oribtal alignment playing a major or determing role.Example Hyperconjucations p oribtal and sigma oribtal must be parallel =to ensure maxium overlap.
In the Transition state , The carbon leaving group(BR) and Beta h on carbon must Anti-periplanar or syn-planar so that the oribtals are parallel for pi formation.
Diaxial product because kinetic forms faster product because it has a lower activation energy .The best path for opening for max oribtal overlap is axial.It has a colinera arrangement.
Slide 20
Stereoisomers-Isomers
Consittutional isomers
isomers with the same moleculer formula but different connectivity of atoms.
Not the same bonding connectivity
can have different combinations of bonds.
stereoisomers
Same bonding connectivity
Are they mirror images?
Yes- are they superimposable
no?-Enatiomers- what is the energy barrier?
break bonds and reform bonds -high-configuration
intercovert by the rotate around single bonds -conformational-low
Not mirror images=Diastereiosmers
high energy barrier-configurational=cis or trans
low energy =conformational