Organic chemistry Flashcards
Constitutional isomerism
- aka Structural isomerism
- Molecules that contain the same atoms but connected in different ways -They have different physical and chemical properites.
Conformational isomerism
- aka. stereoisomer
- Conformational isomerism arises because rotation is possible about sigma bonds.
- Allowing molecules to adopt a variety of shape.
Aliphatic
An organic compound whose structure does not contain benzene or similar structure
The NuE Method analysis
Markonikoff rule
Anti-markonikoff rule
Alkene Reaction Pathway 1:
Carbocation Pathway overview
Alkene Reaction Pathway 1:
Carbocation Pathway full explanation
Describe
SN2 reaction
- (substitution, nucleophilic, bimolecular) is one where a collision between the two reacting species is involved in the rate determining step.
Nu: + Sub-LG —> Nu-Sub + LG¨
- the SN2 reaction is favored in the order 1° > 2° > 3°
Good nucleophilic
- weak bases
- I¨, Br¨, RS¨, HS¨, N3¨, RNH2, CN¨ and PPh3.
SN2 reaction pathway mechanism
concerted mechanism- all the bond making and bond breaking occur simultaneously.
- The transition state has a planar arrangement about the Me, Et and H groups. There are partial negative charges on CN and Cl. Because of the backside attack of the nucleophile, there is a stereochemical (Walden) inversion at carbon in the product.
Carbocation stabilitation
- Neighboring carbon atoms.
- Neighboring carbon-carbon multiple bonds
- Neighboring atoms with lone pairs.
Carbocations are stabilized by neighboring carbon atoms
Carbocations are stabilized by neighboring carbon-carbon multiple bonds
Carbocations are stabilized by adjacent lone pairs
Abbrevations for alkyl group
Hidden hydrogen
The key thing in recognizing hidden hydrogens is that wherever you see less than 4 bonds to carbon, that carbon is going to have hydrogens attached such that there’s a full octet.
Hidden lone pair
Hidden charges
Alkene mechanism pathway reaction 2
Formation of a 3-membered ring
Alkene reaction pathway mechanism 3
The concerted pathway
Summary of alkene reaction
Acyl group
Why are acyl chloride easily attacked by nucleophile?
Nomenclature of ether
The role of the hydroxide ion in a substitution reaction
- OH- acts as Nu
- For example, one of the lone pairs on the oxygen can attack the slightly positive carbon. This leads on to the loss of the bromine as a bromide ion, and the -OH group becoming attached in its place.
The role of the hydroxide ion in an elimination reaction
- OH- acts as strong base
- the hydroxide ion hits one of the hydrogen atoms in the CH3 group and pulls it off. This leads to a cascade of electron pair movements resulting in the formation of a carbon-carbon double bond, and the loss of the bromine as Br-.
pKa table
What makes a good leaving group?
3 classes of nucleophile
- lone pair
- pi bond
- sigma bond
Evaluating resonance with positve charges
Evalutating resonance with negative charges
