Midterm 2 Review Flashcards
(156 cards)
What product predominates under low temperature conditions or when a very sterically-hindered amine is used?
Non-zaitsev kinetic
What product predominates in high temperature conditions?
Zaitsev alkene thermodynamic
How do 1° amines react under acidic conditions?
1° amines can react with aldehydes and ketones to give imines (aka Schiff bases)
• C=N bond
How do 2° amines react with enolizable aldehydes and ketones under acidic conditions?
2° amines can react with enolizable aldehydes and ketones (has alpha hydrogens) to give enamines
• C-N bond & C=C bonds
How do 2° amines react with non-enolizable aldehydes and ketones under acidic conditions?
2° amines can react with non-enolizable aldehydes and ketones (does not have alpha hydrogens) to give iminium ions
• C=N bond
• (+) charge
Alpha hydrogens
Hydrogens on the carbon next door to the carbonyl carbon
Enolizable
Alpha hydrogens present
Carbonyl ->
Reagents: NH3 or 1° amine, pH = 4
N substitutes carbonyl O, N loses 2 hydrogens, N has lone pair, N has its substituent (if applicable), H2O byproduct
Carbonyl with alpha hydrogens ->
Reagents: 2° amine, pH = 4
N substitutes carbonyl O and their bond becomes a single bond, N loses its hydrogen, N has its substituent(s), N has a lone pair, C=C double bond forms between reactant’s most substituted carbons
For intramolecular reactions, number carbons starting with nitrogen as 1 and carbonyl C as last #, form a ring with the number of carbons
Carbonyl with no alpha hydrogens ->
Reagents: 2° amine, pH = 4
N substitutes carbonyl O, N loses its hydrogen, N has its substituent(s), N has a + charge (loses its lone pair)
What would reagents 1) LAH, 2) H3O+ work on?
Strong reducing agent
Aldehyde -> 1° alcohol
Ketone -> 2° alcohol (racemic)
Imine -> amine (double bond becomes H)
Carboxylic acid -> 1° alcohol
Nitrile -> 1° amine (triple bond N becomes single bond NH2 (RNH2))
Ester -> 1° alcohol (double bond O on ester removed, ether O becomes OH and its non-carbonyl R group leaves bound to OH)
Amide -> amine (double bond O chopped off)
What would reagents 1) NaBH4, 2) H3O+ work on?
Mild reducing agent
Aldehyde -> 1° alcohol
Ketone -> 2° alcohol (racemic)
Imine -> amine (double bond becomes H)
What would reagents H2/Pd work on?
Alkene -> alkane
Alkyne -> alkane
Aldehyde -> 1° alcohol
Ketone -> 2° alcohol (racemic)
Imine -> amine (double bond becomes H)
Nitrile -> 1° amine (triple bond N becomes single bond NH2 (RNH2))
Why don’t hydride reducing agents react with carbon-carbon double bonds or triple bonds?
Alkenes & alkynes do not have an electrophile carbon unlike a carbonyl carbon
What would reagent NaBH3CN work on?
Imine -> amine (double bond becomes H)
Whenever you reduce imine -> amine (double bond becomes H), what do you always have to check for?
Racemic
Carbonyl ->
Reagents: NH2NH2, KOH
Double bond O goes away (works on aldehydes and ketones)
Wolf-Kishner
Carbonyl ->
Reagents: Zn(Hg), HCl
Double bond O goes away (works on aldehydes and ketones)
A 3° alcohol will go away and form the most stable C=C double bond from its original point of attachment
Clemmenson Reduction
Enol
C=C-OH
Enol to keto tautomerization
Reagent: cat acid or base
Non-alcoholic C gains a H, double bond moves to in between C and OH which loses its H so it’s just C=O
In keto-enol tautomerization, which product usually predominates and why?
Keto predominates because C=O bond stronger than C=C bond
Keto
Ketone functional group - aldehydes and ketones
In keto-enol tautomerization, when does enol predominate?
In B-diketones, enol predominates due to delocalization of pi bonds
Conjugated hydrogen bonding interaction
Keto to enol tautomerization
Reagent: cat acid or base
Double bond on one keto moves to in between that carbonyl C and most stable position, ex-carbonyl O gains a H