nucleophilic addition - chapter 6 Flashcards
when a nucleophile attacks the carbonyl group which orbital do the electrons enter
the pi* orbital, which breaks the carbonyl bond
how does the electron pair entering the pi* orbital cause the pi bond to break
the electrons break the pi system, destabilising the bond
when the carbonyl bond breaks, where are the electrons transferred
onto the oxygen which forms a negative charge
why are aldehydes more reactive than ketones
- steric hindrance - ketones have two R groups thus having a larger steric hindrance than aldehydes
- aldehydes have one less R group attached to the carbonyl bond - there is less + inductive effect therefore the delta positive charge on the
what is the most important factor to consider when deciding how acidic a molecule is
its resonance structures
why are organometallic reagents powerful nucleophiles
due to the great difference in electronegativities between the carbon group and the metal, the bond is very polar
what effect does protonating the carbonyl group have on a molecule
it makes the carbon more electrophilic
it increases the rate of the reaction
this makes it more attractive for the nucleophile
what does an acid catalyst contribute to a nucleophilic reaction
it protonates the carbonyl group, making the carbonyl more electrophilic
what does having a basic catalyst contribute to a nucleophilic reaction
it de-protonates the nucleophile, making the nucleophile more nucleophilic
why is sodium bisulphate added to aldehydes and ketones
for purification
sulfur atom has lone pair