Alpha Flashcards
Reasons for Aldehyde > Ketone in reactivity
- Polarization (Less R)
- Steric Hindrance -> The H on the aldehyde is much smaller than an R group therefore does not have as much steric hindrance
Function of Halogen to Ketone and Aldehydes
The make it more reactive or any other electronegative element because they make it much more electropositive for nucleophilic attack and like
Diol + Ketone/Aldehyde
Protection of the carbonyl and prevent attack
Function of Thioacetal
- Act as protective groups.
2. By Raney Ni: Thet add H to the C and reduce it specfically
Raney Reagent Function
Specifically reduces the Thioacetal by adding Hydrogens
Imines and Enamines Functional group
Imines - C=N-Y, where Y - H or R
Enamines: C-N-R2, where the next C is made a double bond, detachment of the H is done by a base (base which is the functional group N)
Iminium Ion
C=N-Y-H or R with +ve charge
Oximes
C=N-Y where Y = OH
Hydrazone
C=N-Y, where Y - NHR or NH2
NaBH4 specific addition pattern to aldehyde and ketone
Hydride adds directly to the Carbon (reduces the carbon)
Why is LiAlH4 used dry as a reducing agent?
When wet, it can form H2 gas which can be dangerous. It is much more electropositive than NaBH4, hence, it donates hydrides much more easily
Functional Difference between NaBH4 and LiAlH4
NaBH4 cannot reduce carboxylic acids
LiAlH4 reduces carboxylic acids
Difference between specific reactants acted on
NaBH4 reduces ketones and aldehydes
LiAlH4 reduces esters, carboxylic acids all to aldehydes all the way to alcohols.
Tollen’s Reagent vs. Jones Reagent (na2Cr2O7)
Tollen’s Reagent selectively oxidizes aldehydes and maybe ketones
Jones Reagent oxidizes everything: ketones, alcohols, aldehydes
Change in Cr Oxidation number when oxidizing?
Cr6+ goes to Cr3+
PCC vs Jones Reagent
PCC oxidizes only one step that is: alcohol to aldehyde
Jones reagent goes straight to ester or carboxylic acid
PCC vs Tollen’s reagent
PCC only takes it up one step in terms of alcohol to aldehydes
Tollen’s reagent only attacks aldehydes and ketones and takes it to the end
TBDMSCl function
Protects Alcohol like thioacetals and diols protect ketones/aldehydes
Tosylates and Mesylates chemical form
Tosylates - TsCl
Mesylates - MsCl
Tosylates and Mesylates Function
They both make alcohols a better leaving group
Tosylates and Mesylates vs. TBDMSCl
Tosylates and Mesylates function to make it a better leaving group the alcohol for nucleophilic attack
TBDMSCl protects it like diols and thioacetals
4 Criteria of Aromaticity
- Cyclic
- Planar
- Conjugate
- Huckel’s Rule: 4n + 2 = pi electrons
What is the technique of Benzene and Pyridines to know if something follows Huckel’s Rule?
Always make sure that you have checked all resonance structures to be sure that it is showing the most amount of double bonds. Use Benzene as a model
BH3, THF function
Reduces by one step down by only converting a carboxylic acid down to a ketone or aldehyde but will not take it to the alcohol
BH3, THF vs NaBH4
BH3, THF takes only one step down: Will react with both carboxylic acids and maybe ketone or aldehyde but takes it one step down
NaBH4 cannot react with carboxylic acids that is why it needs LiAlH4. It only breaks down aldehydes or Ketones but cannot attack carboxylic acids
BH3, THF vs LiAlH4
BH3, THF takes carboxylic acids down one step
LiAlH4 rakes it all the way to an alcohol
What does SoCl2 attack in the formation of acid chlorides from Carboxylic acids
O from the C=O binds to the S and the Cl leaves. Cl attacks the C after other reactions and the O an SOCl leave because water has been formed in one case and things are balanced.
Function of DCC
Carboxylic acid plus ammonia can give amides but a much more better way is to use DCC with Nitro groups and carboxylic acids
Beta-Lactam
Amide in a Ring
Biological function of DCC, carboxylic acid and an amino group
Formation of peptide bond. To form this from two amino acids, for the left amino acid, protect its amino group, and for the right amino acid, protect its carboxylic group and then use DCC to form the peptide bond between carboxylic acid and amino group
Amide Functional group
O=C-N
Amide vs Imine
Amide - O=C-N
Imine: C=N-Y
