Alkyl- halides + Guaifenesin chemi 263
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/61
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
62 Terms
What does SN1 stand for
unimolecular nucleophilic substitution
What does SN2 stand for
bimolecular nucleophilic substitution
How many steps does SN1 occur in
two steps
How many steps does SN2 occur in
one concerted step
What is the rate law for SN1
Rate = k[RX]
What is the rate law for SN2
Rate = k[RX][Nu⁻]
What intermediate forms in SN1
carbocation
What intermediate forms in SN2
none, it is concerted
What stereochemistry results from SN1
racemization
What stereochemistry results from SN2
inversion of configuration
Why do tertiary alkyl halides favor SN1
they form stable carbocations
Why do primary alkyl halides favor SN2
low steric hindrance
Why do tertiary alkyl halides not undergo SN2
too much steric hindrance
Why is iodide the best leaving group
it is large and stable
What reaction is used to synthesize 1-iodobutane
1-bromobutane + NaI → 1-iodobutane + NaBr
What mechanism synthesizes 1-iodobutane
SN2
Why is 1-bromobutane used in this reaction
it is primary and favors SN2
What is the role of NaI
provides iodide nucleophile
Why is acetone used
it is a polar aprotic solvent that favors SN2
Why does acetone favor SN2
it does not strongly solvate nucleophiles
Why does NaBr precipitate during the reaction
it is insoluble in acetone
Why is NaBr precipitation important
it drives equilibrium toward products
Why is reflux used
to heat reaction without losing solvent
Why wash with water
to remove acetone and salts
Why wash with sodium bisulfite
to remove iodine impurities
Why dry with Na₂SO₄
to remove water
Why distill the final product
to purify 1-iodobutane
What reagent is used for SN2 testing
NaI in acetone
What indicates an SN2 reaction occurred
precipitate formation
What reagent is used for SN1 testing
AgNO₃ in ethanol
What indicates an SN1 reaction occurred
AgX precipitate formation
Why does ethanol favor SN1
it is a polar protic solvent
What is the fastest SN2 substrate
1-bromobutane
What is the fastest SN1 substrate
tert-butyl chloride
Which substrate reacts quickly in both SN1 and SN2
benzyl chloride
What reaction synthesizes guaifenesin
Williamson ether synthesis
What is Williamson ether synthesis
reaction of an alkoxide or phenoxide with an alkyl halide
What mechanism does Williamson ether synthesis follow
SN2
What does guaifenesin do
loosens and thins mucus
How many enantiomers does guaifenesin have
two
What form of guaifenesin is synthesized in lab
racemic mixture
What is the starting aromatic compound for guaifenesin synthesis
guaiacol
What base is used in guaifenesin synthesis
NaOH
Why is NaOH used
to deprotonate guaiacol
What intermediate forms after deprotonation
phenoxide ion
Why is phenoxide a strong nucleophile
it carries a negative charge on oxygen
What alkyl halide is used in guaifenesin synthesis
3-chloro-1,2-propanediol
What is the first step of guaifenesin synthesis
deprotonation of guaiacol
What is the second step of guaifenesin synthesis
SN2 attack on alkyl halide
What is the leaving group in guaifenesin synthesis
chloride ion
Why does guaifenesin synthesis proceed by SN2
the alkyl halide is primary
Why does it not proceed by SN1
primary carbocation is unstable
Why is hexane added during extraction
to precipitate guaifenesin
How is guaifenesin isolated
vacuum filtration
Why is water unusual for SN2 reactions
it is polar protic and weakens nucleophiles
What are better solvents for SN2 reactions
acetone, DMSO, DMF
Why use NaOH instead of a weaker base
to fully generate phenoxide
Why doesn’t phenoxide deprotonate alcohol groups
alcohols are less acidic than phenols
What is the main advantage of Williamson ether synthesis
efficient ether formation
What is the main limitation of Williamson ether synthesis
requires an unhindered substrate
why is NaoH used in guaifenesin?
to deprotation the OH group on guaiacol
how it glycerol formed in guaifenesin?
The Cl gets replaced by a OH from NaOH via Sn2