Substitution Rxns Flashcards
Do SN2 rxns happen in 1 step or 2?
1 concerted step
Do SN1 rxns happen in 1 step or 2?
2 steps (or more if the leaving group is shit)
Does SN2 rxn favor front side attack or backside attack?
backside
Does SN2 rxn make inverted products?
yes; backside attack results in inversion of configuration
What level of substitution does SN2 rxn favor?
CH3 > primary > secondary»_space; tertiary
Does SN2 rxn create carbocation intermediate?
No
Does SN1 rxn create carbocation intermediate?
Yes
Does SN2 rxn favor weak nucleophile or strong nucleophile?
strong
Does SN1 rxn favor weak nucleophile or strong nucleophile?
weak
which rxn gives racemixture: SN1 or SN2?
SN1 (because the nucleophile attacks from the front and the back)
What level of substitution does SN1 rxn favor?
tertiary > secondary > primary»_space; CH3
What happens in a substitution rxn?
A leaving groups gets kicked off and replaced by a good nucleophile.
what are polar protic solvents?
solvents that have H directly connected to an electronegative atom
exp. NH3, H2O, CH3OH, EtOH
which substitution rxn favors polar protic solvents?
SN1
what are polar Aprotic solvents?
solvents that DO NOT have H directly connected to an electronegative atom
exp organic solvents (acetone, DMF, DMSO)
which substitution rxn favors polar Aprotic solvents?
SN2
what makes a strong nucleophile strong?
It’s charged; it’s ionic; it came from an ionic compound
what makes a weak nucleophile weak?
it’s neutral; it did not come from an ionic compound
what’s the difference between E2 and SN2?
in E2, the substrate acts like a base (taking a hydrogen) bc it’s too big/stericly hindered to act like. a nucleophile.
In SN2, the substrate acts like a nucleophile, (taking the leaving group)
what level of substituted-ness to E1 and SN1 rxns prefer?
tertiary
