Ch14: Epoxides & Ethers

Question 1

Ether compound structure

Answer 1

R-O-R’

Question 2

Ethers other than ______ are relatively _______ therefor commonly used as ______

Answer 2

epoxides, unreactive, solvents

Question 3

ethers have ______ boiling points than alcohols of similar molecular weights because no ________

Answer 3

lower, hydrogen bonding

Question 4

ethers solvate ______

alcohols solvate _______

Answer 4

cations, not anions

cations and anions

Question 5

ethers are usually _____ towards strong bases, therefore used as solvent for strong bases such as _______

Answer 5

unreactive, Grignard reagent

Question 6

Ethers commonly complex with _______ to stabilize the compound, ex: _______

Answer 6

grignard reagents, or electrophiles; ex: BH3.THF

Question 7

_____ ethers are large cyclic polyethers that specifically solvate _____

Answer 7

crown, metal cations

Question 8

cyclohexene —peroxybenzoic acid—> ????

Answer 8

cyclohexene oxide

Question 9

ethylene + peroxybenzoic acid —>

Answer 9

ethylene oxide/ozirane/1,2-epoxyethane + benzoic acid

Question 10

oxetane

Answer 10

more reactive than larger cyclic ethers and open-chain ethers, but not as much as oxiranes
four-membered ring

Question 11

furans (oxylanes), ex:______ hydrated, _____ unsaturated

Answer 11

five-membered ring

ex: tetrahydrofuran (THF), 3-methoxyfuran

Question 12

pyrans (oxanes), ex: ______ hydrated, ______ unsaturated

Answer 12

six-membered ring

ex: tetrahydropyran (THP), 4-methylpyran

Question 13

dioxanes, ex: ______ most commmon, ______ toxic group

Answer 13

six-membered rings

ex: 1,4-dioxane, dibenzo-1,4-dioxane/dioxin

Question 14

IR identified by _____ at 1000-1200cm-1, no____ or _____

Answer 14

strong C-O stretch, no C=O or O-H

Question 15

three fragmentations processes in mass spec

Answer 15

alpha cleavage: loss of either of the alkyl groups next to O produces oxonium ion
loss of an alkyl group: fragment next to O produces oxonium ion or alkyl cation
alpha cleavage + loss of group

Question 16

Williamson ether synthesis

Answer 16

SN2 attack of alkoxide ion on unhindered primary alkyl halide or tosylate

Question 17

cyclohexanol —[1]Na–>—[2]CH3CH2OTs–> ?????

Answer 17

ethoxycyclohexane

Question 18

3,3-dimethylpentan-2-ol —[1]Na–>—[2]CH3I–> ?????

Answer 18

2-methoxy-3,3-dimethylpentane

Question 19

a phenol can be used as the ______ fragment but not the ______ fragment for Williamson ether synthesis

Answer 19

alkoxide, halide ( can get attacked and joined to, but cannot be the added compound)

Question 20

-H2C=C=H2- —??? in ??? —> -HC(-AcOHg)-CH(-O-R)- —-???–> -C(H)H-C(H)OR-

Answer 20

Hg(OAc)2 in ROH, NaBH4

Question 21

CH3(CH2)3-CH=CH2 —[1]Hg(OAc)2, CH3OH–>—[2] NaBH4—> ?????
Mark or anti-Mark?

Answer 21

CH3(CH2)3-CH(-OCH3)-CH3

Markovnikov

Question 22

Biomolecular condensation ______ in ______ gives you _____ + ________

Answer 22

2 primary alcohols in acid gives you symmetrical ether + water

Question 23

ethers are cleaved by ___ or ___ to give you ___ or ____

Answer 23

HBr or HI to give you alkyl bromides or alkyl iodides

Question 24

R-O-R’ + H-X ?????

Answer 24

protonated ether

R-O(H)-R (positive cation)

Question 25

R-O(H)-R' + X- ---> ????

Answer 25

X-R + H-O-R'

Question 26

H-O-R' + ???? --> X-R' + H2O

Answer 26

HX

Question 27

cyclopentyl ethyl ether ---> Br-CH2-CH3 and 1-bromocyclopentane MECHANISM (6 steps)

Answer 27

[1] H-Br protonate O of ether [2] Br- attacks less hindered C, cleaves O-C bond producing Br-CH2-CH3 and cyclopentan-1-ol [3] H-Br protonate O [4] water leaves forming cation [5] Br- binds to cation +, forming 1-bromocyclopentane

Question 28

phenyl ethers react with ____ and ____ to give alkyl halides and _____

Answer 28

H-I and H-Br, phenols, phenols do not react further

Question 29

ethyl phenyl ether ---> phenol and ethyl bromide MECHANISM (2 steps)

Answer 29

[1] H-Br protonates ether | [2] Br- attacks less hindered C producing phenol and Br-CH2CH3

Question 30

ether --- excess O2 ---> ???? and ???? | R-O-CH2-R'

Answer 30

hydroperoxides R-O-CH(OOH)-R' dialkly peroxide R-O-O-CH2-R'

Question 31

thioethers another name

Answer 31

sulfides, S replaces O

Question 32

silyl ether structure, useful for as _____ because they are more easily ______ and _____

Answer 32

R-O-(R')Si(R')-R, Si replaces a CH2 | protecting group for alcohols, formed and hydrolyzed

Question 33

thiolate ion formation, useful in producing _____ products with inversion or retension

Answer 33

thiol + Na+-OH | SN2, inversion

Question 34

peroxide + acid, good _____ for sulfides (mild ____ agent)

Answer 34

oxidizing agents, reducing

Question 35

Sulfide ---???? in ????--> sulfoxide | stability?

Answer 35

H202 and CH3-COOH peroxide and acetic acid R-S(=O)-R' R-S(-O)-R positive cation

Question 36

sulfoxide ---H2O2 and CH3COOH-->? | stability?

Answer 36

sulfone stabilized by resonance | R-(O=)S(=O)-R' R-(O-)S(-O)-R 2+positive cation

Question 37

ozonolysis of alkene | 1-methyl cyclohex-1-ene ---???--->??---> dimethyl sulfide and CH3(O=)C-(CH2)4-C(=O)H what happened to the first product?

Answer 37

O3 to give oxonide, dimethyl sulfoxide, sulfide breaks the ring, and is oxidized to dimethyl sulfoxide

Question 38

sulfide + ??? ---SN2---> sulfonium salt

Answer 38

alkyl halide

Question 39

sulfonium salt + nucleophile --->? | Nuc: + CH3-S(R)-R --->?

Answer 39

alkyl (nuc) + sulfide | Nuc-CH3 + R-S-R

Question 40

R-OH + [1] _____ in _____ -----> R-O-TIPS + [2] ____ in _____-----> R-OH + (i-Pr)3SiF [1] does what? [2] does what?

Answer 40

(i-Pr)3SiCl aka TIPSCl in Et3N: Bu4N+-F in water [1] TIPS replaces H, protecting the alcohol while a different part of the compound is changed [2] Bu4N+-F removes TIPS and H2O reforms the alcohol

Question 41

alkene + peroxyacid --->??? | >C=C< + R-(O=)C-O-O-H

Answer 41

epoxide + acid | >COC< + R-(O=)C-O-H

Question 42

MCPBA

Answer 42

meta-chloroperoxybenzoic acid chlorine-benzene ring-C(=O)-O-O-H

Question 43

cyclohexene -> epoxycyclohexane

Answer 43

MCPBA in CH2Cl2

Question 44

MMPP

Answer 44

magnesium monoperoxyphthalate, water-soluble peroxyacid

Question 45

halohydrin + base ???? ---> epoxide >C(-X)-C(< )-OH *opposite sides* + -OH

Answer 45

[1] dehydrogenation | [2] O attacks opposite C, halide leaves forming an epoxide

Question 46

___ + ___ in _____ --> chlorohydrin intermediate? ex: trans-chorohydrin (Cl and OH opposite sides)

Answer 46

alkene + dichloride in water produces a chloronium ion (Cl epoxide) ex: cyclopentene + chlorine water

Question 47

[1] chlorohydrin + ???--> [2] ---> expoxide

Answer 47

[1] base | [2] alkoide, O attacks the opposite C, halide leaves

Question 48

acid + epoxide in water --> ???? | stereochemistry?

Answer 48

opens ring, trans-diol | anti

Question 49

alkene + peroxyacid in H+ , H20 --->?

Answer 49

cis-diol

Question 50

acid + epoxide in alcohol --> ???? stereochemistry? alkoxy group bonds to the _____ carbon

Answer 50

opens ring attaches alcohol (O-R) and form hydroxy group (add H) anti OR binds to more highly substituted, OH binds to less substituted

Question 51

ethers do not form alcohols easily instead ____ are used

Answer 51

epoxides

Question 52

strong base + epoxide ---> ????

Answer 52

trans-diol

Question 53

these solvents can open epoxides

Answer 53

acids, strong bases, alkoxide ions (ex: CH3-O-+Na in CH3OH), amines, grignard, organolithium reagents

Question 54

HOCH2CH2N:H2 + oxirane ---> [1] + oxirane ---> [2]

Answer 54

[1] (HOCH2CH2)2N:H | [2] (HOCH2CH2)3N:

Question 55

basic conditions orientation of epoxide opening attacks how? give?

Answer 55

attack less hindered carbon | SN2 displacement, give alcohols, OR binds to less substituted, OH binds to more substituted

Question 56

acidic conditions orientation of epoxide opening attacks how? give?

Answer 56

attacks the protonated carbon of the epoxide , give alcohols,

Question 57

[1] Grignard reagent + epoxide in _____ ---->[2]H20 ---> ????

Answer 57

[1] ether | [2] ring-opened alcohol

Question 58

Organolithium and grignard reagents attack the ______ carbon of an epoxide, which is more specific?

Answer 58

less hindered, R bonds less substituted, OH bonds more substituted organolithium is more specific

Question 59

methyl oxirane + H+ in CH3-OH --->??

Answer 59

2methoxypropan-1-ol | CH3-CH(-OCH3)-CH2-OH

Question 60

methyl oxirane + CH3-O-+Na in CH3OH--->??

Answer 60

1methoxypropan-2-ol | CH3-CH(-OH)-CH2-OCH3

Question 61

methyl oxirane + [1] R-MgBr -->[2]-????-->???

Answer 61

[2] H30+ CH3-CH(OH)-CH2-R R bonds to the less substituted carbon