Exam 1 - Epoxides Flashcards
In ___ ___ openings of epoxides, the reagents include H2SO4 and CH3OH.
Acid Catalyzed
In Base Catalyzed openings of epoxides, the OH- attacks the ___ substituted side of the epoxide.
less
NaH = Good Base, ___ a Good Nucleophile.
NOT
___ nucleophiles are needed in Acid Catalyzed openings of epoxides, since the reaction is now under acidic conditions.
Weaker
Acid Catalyzed openings of epoxides lead to ___ mechanism, and ___ of stereochemistry.
SN1, inversion
In ___, an epoxide with a Cl can react with a nucleophile in order to swap the Cl with the nucleophile. You can then add ANOTHER nucleophile in order to open the epoxide.
Epichlorohydrin
Lewis Acid Catalyzed openings of epoxides attack the ___ substituted side of the epoxide.
more
A(n) ___ is a 3-membered cyclic ether.
epoxide
A ___ alkene will produce a trans epoxide.
E
An epoxide is a ___ ___ ___.
3-membered cyclic ether
Epoxides can behave as ___ in reactions.
electrophiles
Lewis Acid Catalyzed openings of epoxides allow us to use ___ we could not use under acidic conditions.
nucleophiles
A meso compound is overall ___ but withat least ___ ___ ___.
achiral, 2 chiral centers
Base Catalyzed openings of epoxides can also happen to produce H at the less substituted side (a “nucleophilic H-“). The reagents used here are 1) ___, then 2) ___.
1) LiAlH4 2) H3O+
In Acid Catalyzed openings of epoxides, the CH3OH attacks the ___ substituted side of the epoxide.
more
In Base Catalyzed openings of epoxides, the epoxide reacts with ___ and ___.
base (i.e. NaOH) and H2O
A ___ alkene will produce a cis epoxide (meso compound).
Z
Treating a halohydrin (OH and H on adjacent Cs) with a ___ will produce an epoxide.
base (NaOH, K2CO3, NaH)
Lewis Acid Catalyzed openings of epoxides use the reagents ___ (or ___) and ___.
AlCl3, BF3-OEt2, ethanol
Examples of Nucleophiles:
OR, OH, CN, N3, SR, I, Br, Cl, H (via LiAlH4), alkyne-R
Carbonyl groups conjugated to alkenes are ___ ___. They act as withdrawing groups.
electron poor
Acid Catalyzed openings of epoxides include ___ and ___.
H2SO4 and CH3OH
In Epichlorohydrin, an epoxide with a ___ can react with a ___ in order to swap the ___ with the ___. You can then add ANOTHER ___ in order to open the epoxide.
Cl, nucleophile, Cl, nucleophile, nucleophile
The most common way to make epoxides is through a peracid reaction, where you add ___ to an ___.
mCPBA to an alkene
In peracid reactions, the relative stereochemistry of the epoxide is ___ from the alkene.
retained (Z -> cis, E -> trans)
A Z alkene will produce a ___ ___ (___ ___).
cis epoxide (meso compound)
Epoxidations with mCPBA work best with ___ alkenes, AKA ___ ___ alkenes.
electron-rich, more substituted
Treating an alkene with Br2 and H2O will produce an ___ with ___ and ___ on adjacent Cs. Then treat the same molecule with NaOH to produce an ___.
alkane with OH and Br on adjacent Cs, epoxide
The most common way to make epoxides is through a ___ ___.
peracid reaction
A E alkene will produce a ___ ___.
trans epoxide
In ___ ___ openings of epoxides, the epoxide reacts with base (i.e. NaOH) and H2O.
Base Catalyzed
Base Catalyzed openings of epoxides lead to ___ via ___.
inversion via SN2
