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Orgo II > Ch14: Epoxides & Ethers > Flashcards

Ch14: Epoxides & Ethers Flashcards

1
Q

Ether compound structure

A

R-O-R’

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2
Q

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

A

epoxides, unreactive, solvents

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3
Q

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

A

lower, hydrogen bonding

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4
Q

ethers solvate ______

alcohols solvate _______

A

cations, not anions

cations and anions

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5
Q

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

A

unreactive, Grignard reagent

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6
Q

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

A

grignard reagents, or electrophiles; ex: BH3.THF

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7
Q

_____ ethers are large cyclic polyethers that specifically solvate _____

A

crown, metal cations

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8
Q

cyclohexene —peroxybenzoic acid—> ????

A

cyclohexene oxide

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9
Q

ethylene + peroxybenzoic acid —>

A

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

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10
Q

oxetane

A

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

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11
Q

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

A

five-membered ring

ex: tetrahydrofuran (THF), 3-methoxyfuran

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12
Q

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

A

six-membered ring

ex: tetrahydropyran (THP), 4-methylpyran

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13
Q

dioxanes, ex: ______ most commmon, ______ toxic group

A

six-membered rings

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

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14
Q

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

A

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

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15
Q

three fragmentations processes in mass spec

A

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

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16
Q

Williamson ether synthesis

A

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

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17
Q

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

A

ethoxycyclohexane

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18
Q

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

A

2-methoxy-3,3-dimethylpentane

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19
Q

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

A

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

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20
Q

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

A

Hg(OAc)2 in ROH, NaBH4

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21
Q

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

A

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

Markovnikov

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22
Q

Biomolecular condensation ______ in ______ gives you _____ + ________

A

2 primary alcohols in acid gives you symmetrical ether + water

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23
Q

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

A

HBr or HI to give you alkyl bromides or alkyl iodides

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24
Q

R-O-R’ + H-X ?????

A

protonated ether

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

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25
Q

R-O(H)-R’ + X- —> ????

A

X-R + H-O-R’

26
Q

H-O-R’ + ???? –> X-R’ + H2O

A

HX

27
Q

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

A

[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

28
Q

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

A

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

29
Q

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

A

[1] H-Br protonates ether

[2] Br- attacks less hindered C producing phenol and Br-CH2CH3

30
Q

ether — excess O2 —> ???? and ????

R-O-CH2-R’

A

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

31
Q

thioethers another name

A

sulfides, S replaces O

32
Q

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

A

R-O-(R’)Si(R’)-R, Si replaces a CH2

protecting group for alcohols, formed and hydrolyzed

33
Q

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

A

thiol + Na+-OH

SN2, inversion

34
Q

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

A

oxidizing agents, reducing

35
Q

Sulfide —???? in ????–> sulfoxide

stability?

A

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

36
Q

sulfoxide —H2O2 and CH3COOH–>?

stability?

A

sulfone stabilized by resonance

R-(O=)S(=O)-R’ R-(O-)S(-O)-R 2+positive cation

37
Q

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?

A

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

38
Q

sulfide + ??? —SN2—> sulfonium salt

A

alkyl halide

39
Q

sulfonium salt + nucleophile —>?

Nuc: + CH3-S(R)-R —>?

A

alkyl (nuc) + sulfide

Nuc-CH3 + R-S-R

40
Q

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

[1] does what?
[2] does what?

A

(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

41
Q

alkene + peroxyacid —>???

>C=C< + R-(O=)C-O-O-H

A

epoxide + acid

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

42
Q

MCPBA

A

meta-chloroperoxybenzoic acid

chlorine-benzene ring-C(=O)-O-O-H

43
Q

cyclohexene -> epoxycyclohexane

A

MCPBA in CH2Cl2

44
Q

MMPP

A

magnesium monoperoxyphthalate, water-soluble peroxyacid

45
Q

halohydrin + base ???? —> epoxide

> C(-X)-C(< )-OH opposite sides + -OH

A

[1] dehydrogenation

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

46
Q

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

A

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

47
Q

[1] chlorohydrin + ???–> [2] —> expoxide

A

[1] base

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

48
Q

acid + epoxide in water –> ????

stereochemistry?

A

opens ring, trans-diol

anti

49
Q

alkene + peroxyacid in H+ , H20 —>?

A

cis-diol

50
Q

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

A

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

51
Q

ethers do not form alcohols easily instead ____ are used

A

epoxides

52
Q

strong base + epoxide —> ????

A

trans-diol

53
Q

these solvents can open epoxides

A

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

54
Q

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

A

[1] (HOCH2CH2)2N:H

[2] (HOCH2CH2)3N:

55
Q

basic conditions orientation of epoxide opening
attacks how?
give?

A

attack less hindered carbon

SN2 displacement, give alcohols, OR binds to less substituted, OH binds to more substituted

56
Q

acidic conditions orientation of epoxide opening
attacks how?
give?

A

attacks the protonated carbon of the epoxide , give alcohols,

57
Q

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

A

[1] ether

[2] ring-opened alcohol

58
Q

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

A

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

59
Q

methyl oxirane + H+ in CH3-OH —>??

A

2methoxypropan-1-ol

CH3-CH(-OCH3)-CH2-OH

60
Q

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

A

1methoxypropan-2-ol

CH3-CH(-OH)-CH2-OCH3

61
Q

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

A

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

Orgo II (8 decks)

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