Exam 1 - Epoxides

Question 1

In ___ ___ openings of epoxides, the reagents include H2SO4 and CH3OH.

Answer 1

Acid Catalyzed

Question 2

In Base Catalyzed openings of epoxides, the OH- attacks the ___ substituted side of the epoxide.

Answer 2

less

Question 3

NaH = Good Base, ___ a Good Nucleophile.

Answer 3

NOT

Question 4

___ nucleophiles are needed in Acid Catalyzed openings of epoxides, since the reaction is now under acidic conditions.

Answer 4

Weaker

Question 5

Acid Catalyzed openings of epoxides lead to ___ mechanism, and ___ of stereochemistry.

Answer 5

SN1, inversion

Question 6

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.

Answer 6

Epichlorohydrin

Question 7

Lewis Acid Catalyzed openings of epoxides attack the ___ substituted side of the epoxide.

Answer 7

more

Question 8

A(n) ___ is a 3-membered cyclic ether.

Answer 8

epoxide

Question 9

A ___ alkene will produce a trans epoxide.

Answer 9

E

Question 10

An epoxide is a ___ ___ ___.

Answer 10

3-membered cyclic ether

Question 11

Epoxides can behave as ___ in reactions.

Answer 11

electrophiles

Question 12

Lewis Acid Catalyzed openings of epoxides allow us to use ___ we could not use under acidic conditions.

Answer 12

nucleophiles

Question 13

A meso compound is overall ___ but withat least ___ ___ ___.

Answer 13

achiral, 2 chiral centers

Question 14

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) ___.

Answer 14

1) LiAlH4 2) H3O+

Question 15

In Acid Catalyzed openings of epoxides, the CH3OH attacks the ___ substituted side of the epoxide.

Answer 15

more

Question 16

In Base Catalyzed openings of epoxides, the epoxide reacts with ___ and ___.

Answer 16

base (i.e. NaOH) and H2O

Question 17

A ___ alkene will produce a cis epoxide (meso compound).

Answer 17

Z

Question 18

Treating a halohydrin (OH and H on adjacent Cs) with a ___ will produce an epoxide.

Answer 18

base (NaOH, K2CO3, NaH)

Question 19

Lewis Acid Catalyzed openings of epoxides use the reagents ___ (or ___) and ___.

Answer 19

AlCl3, BF3-OEt2, ethanol

Question 20

Examples of Nucleophiles:

Answer 20

OR, OH, CN, N3, SR, I, Br, Cl, H (via LiAlH4), alkyne-R

Question 21

Carbonyl groups conjugated to alkenes are ___ ___. They act as withdrawing groups.

Answer 21

electron poor

Question 22

Acid Catalyzed openings of epoxides include ___ and ___.

Answer 22

H2SO4 and CH3OH

Question 23

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.

Answer 23

Cl, nucleophile, Cl, nucleophile, nucleophile

Question 24

The most common way to make epoxides is through a peracid reaction, where you add ___ to an ___.

Answer 24

mCPBA to an alkene

Question 25

In peracid reactions, the relative stereochemistry of the epoxide is ___ from the alkene.

Answer 25

retained (Z -> cis, E -> trans)

Question 26

A Z alkene will produce a ___ ___ (___ ___).

Answer 26

cis epoxide (meso compound)

Question 27

Epoxidations with mCPBA work best with ___ alkenes, AKA ___ ___ alkenes.

Answer 27

electron-rich, more substituted

Question 28

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 ___.

Answer 28

alkane with OH and Br on adjacent Cs, epoxide

Question 29

The most common way to make epoxides is through a ___ ___.

Answer 29

peracid reaction

Question 30

A E alkene will produce a ___ ___.

Answer 30

trans epoxide

Question 31

In ___ ___ openings of epoxides, the epoxide reacts with base (i.e. NaOH) and H2O.

Answer 31

Base Catalyzed

Question 32

Base Catalyzed openings of epoxides lead to ___ via ___.

Answer 32

inversion via SN2