11/7 Flashcards
(31 cards)
for hydrate formation, what is the nucleophile
water
for acetal formation, what is the nucleophile
alcohol
for imine formation, what is a nucleophile
primary amine
for enamine formation, what is the nucleophile
secondary amine
for cyanohydrin formation, what is the nucleophile
cyanide ion
whats a good application of cyanohydrins
creates carbon-carbon bonds
why must we use a different method of creating a cyanohydrin other than HCN
HCN is a weak acid, it is a weak source of the cyanide ion nucleophile
- equilibrium favors formation of reactants
-does not dissociate all the way
how can we accelerate the formation of a cyanohydrin
use an ionic source like NaCN as a source of nucleophile
what are the reagents for cyanohydrin formation
1) NaCN and H2SO4
why are wittig reactions important
they make carbon carbon bonds
what is a phosphorus ylide
it is the reagent for a wittig reaction
it has a positive and negative charge on the same molecule
the negative charge on the carbon is the nucleophile
what is the overall transformation in a wittig reaction
a aldehyde or ketone is transformed into an alkene
what do we need to do for the reagents in a wittig reaction
the triphenyl phosphine needs to be generated in situ
what happens to the oxygen on the carbonyl in the wittig reaction
it becomes a byproduct to make triphenylphosphine oxide
how do you prepare a phosphorous ylide
react triphenyl phosphine with a 1° or 2° alkyl halide and a base like n-butyllithium or potassium t-butoxide
what is n butyl lithium
it is a 4 carbon chain with a carbanion on the end of the carbon, it is “normal” and it acts as a common strong base
what is C4H9Li
n-butyllithium
what is the clemmenson reduction
it is the reduction of a carbonyl using acidic conditions
Zn, Hg/ HCl
what is the wolff kichner reduction
reduction of a carbonyl using basic conditions (KOH) and hydrazine (NH2-NH2)
what is the nucleophile in a wolff kichner reduction
hydrazine NH2-NH2
what is the intermediate in the wolff kichner reduction
hydrazone intermediate
how is the wolff kichner related to imine formation
there is a nitrogen double bond imine functional group as an intermediate step
what is the mechanistic pathway of carboxylic acids
nucleophilic acyl substitution
why do carboxylic acids and derivatives undergo nucleophilic substitution?
They have good leaving groups, unlike ketones and aldehydes, which have poor leaving groups
