mcat organic chemistry chapter 7 alcohols ethers
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- ROH are
- alcohols
- -OH is?
- hyroxyl group
- alcohol can be thought of as a subst ____________
- water molecule
-
iupac system
alcohols are ? - ol
- because the -OH gr has high priority, its carbon must be?
- in the carbon backbone with the low numb poss
- ethanol can also be called?
- ethyl alcohol
- ArOH is called?
- phenol
- bp of alcohols are signif are higher than alkanes bec?
- hydrogen bonding
- the more hydroxy gr a molec has the more ?
- hydrogen bonding
- hydrogen bonds form on the "phone" the "fon" means?
- h with F, O, or N will make hydrogen bonds
-
ROH
alcohols are weakly? - acidic
- strong acids have ___________ Ka's
- high
- strong acids have _________ pKas
- small
- the hydroxyl gr of _________ are more acidic than alcohols
- phenols
- the hydroxy gr of phenols are more acidic than alcohols due to ?
- resonance struct that distr negat ch thr the ring.
-
for alcohols
electr donating gr ______________ the alkoxide anion - destabl
- acidity ____________ as more alkyl gr are attached
- decre
- why does acidity decr as more alkyl gr are added to an alcohol?
- bec electr donat alkyl gr destab the alkoxide anion
- __________ stabilize the alkoxy anion, mak the alcoh more acidic
- electr withdraw
- what kind of gr make the alcohol more acidic?
- electr withdraw
- phenols can _______ with inorganic bases like NaOh
- form salts
- what are the 3 big mech for alcohols?
-
1. Sn1, Sn2 nucl subst
2. electr addit to doubl bond
3. nucl addit to carbonyl -
CH3Br + OH- ----> CH3OH + Br-
this is a ? - nucleophilic substition
- aloohols can form from _____________ to a double bond
- electrophilic addit to a double bond
- an alcohol can form from a __________ to a carbonyl
- nucleoph addit
-
levels of oxidation
primary alcohos----- ? ----carboxylic acids - aldehydes
-
oxidat levels
second alcohols---- ? - ketons
- who is more oxidized an aldehye or a carboxylic acid?
- carboxylic acid
- more bonds to ________ means more oxidized
- oxygen
- methanol can be made by destruct distillation of?
- wood
- methanol is _________ alcohol
- wood
- methanol is toxic and can cause?
- blindness
- alcohols can be prep via?
-
1. addit of water to double bonds
2. addit of organometallic comp to carbonyl gr - alcoh can be made by reducing?
- aldehydes, ketones, carboxylic acids, esters
- aldehydes, ketones, carbox ac, esters can be red to?
- alcohols
- to reduc aldeh, ketones, carb acids, esters to alcoh you use?
-
LiAlH4, LAH,
NaBH4 - LAH is?
- lithium aluminum hydride
- NaBH4 is?
- sodium borohydride
-
LAH and NaBH4
which is more powerful and diff to work with? - LAH
-
LAH and NaBH4
which is more selective? - NaBH4
- __________ will reduce carboxy ac and esters to alcoh
- LAH
- ___________ will not reduce carbox ac and esters to alcoh
- NaBH4
-
maing phenols w arylsulfonic ac with hot NaOH
whats the disadvant? - it will destroy most funct gr other than the phenol gr and its alkylated deriv
- how do you make phenols?
- with arylsulfonic ac and hot NaOH
- whats a better way of making phenols than by using arylsulfonic acids with hot NaOH?
- hydrolysis of diazonium
- hydrolysis of diazonium uses what reagants?
- HNO2/HSO4 followed by H3O
- hydrolysis of a diazonium salt will turn an aromatic NH2 gr into a?
- OH group
- an alcoh can be made into an alkene suing?
- a strong acidic solution
-
alcohol---- alkene
this process of getting rid of the alcoh is called? - dehydration
- the mech of dehydration of an alcoho is?
-
E1
and goes thr a protonated alcohol - alcohols are usually dehydrated with ?
- H2SO4
-
alcohol dehdrat will have 2 prod.
what will be the maj one? - the more stable alkene. occurs thr movement of a proton to prod the more stable second carbocat
- E1 you want to form the most stable?
- carbocation
- displac of hydroxy gr in subst react is rare bec?
- hydrox ion is a poor leav gr
- to displace a OH gr you have to?
- make it a good leaving gr by protonating it to make H2O
- by protonating an alcohol you make it?
- a good leav gr
- a protonated alcohol is good for a _____________ react
- Sn1
- alcohol conv to tosylate (p-toluenesulfonate) gr is a good leav gr for a ___________ react
- Sn2
- what 3 ways can you turn an alchol into a good leav gr for an Sn1/Sn2 react?
-
1. protonate it
2. conv it to tosylate
3. form an inorg ester -
alc to alky halide
you change the alc to a? - inorganic ester. which will then do SN2
- alcohols plus what will make an intermed inorgan ester and HCL?
- thionyl chloride
- Thionyl chloride is used to?
- make an alcohol into an inorg ester and then an alkyl halide
- SOCl2 is?
- thionyl chloride
- thionyl chloride is?
- SOCl2
- to make an alc into a alkyl bromide you react alc w?
- PBr3
- phenols undergo electr aromatic?
- substit react. it has lone pairs it can donate to the ring
-
phenol
OH gr is __________, ___________ direct ring const -
strongly activating
ortho/para direct -
t or f
phenols are good subst for electr aromatic subst - t
- oxid of alcohols usually is done with?
- some form of chromium (VI)
- primary alcohols to aldehyde is done w?
- PCC
- PCC is
- pyridium chlorochromate
- C5H6NCrO3Cl is ?
- PCC
- PCC will make what from an alcholo?
- aldehyde
- alcohol plus PCC will make?
- aldehyde
- alcohol + PCC will not overoxidize to?
- an carboxylic acid
-
oxid of alc
PCC versus KMnO4 - KMno4 will oxid to carboxy acid
- PCC can make secod alc into?
- ketones
- PCC and also ___________ can both be used to make second alcholos
- alkali dichromate salt
- alcohol + sodium dichromate salt ----->
- carboxy acid
- when you see a transition metal like Cr or Mn with lots of oxy think of?
- oxidation
-
Cr2O7, Cro3, MnO4
when you see these, think of? - oxidation
- Na2Cr2O7 is?
- sodium dichromate salt
- second alcohol plus Na2Cr2O7/H2SO4 will make a
- ketone
- CrO3/H2SO4/acetone is __________ reagent
- Jones reagent
- Jones reagent is?
- CrO3/H2SO4/acetone
- primary alc + CrO3/H2SO4/acetone --->
- carboxy acid
- second alcholo +CrO3/H2SO4/acetone --->
- ketone
- phenols plus oxidizing reagents will make?
-
quinones.
which is a benzene gr with c=O on it. - ether is
- 2 alkyl or aryl gr bonded to an oxy
- ROR is a?
- ether
- general formula for an ether is?
- ROR
- you can think of ether as being a disubstituted ?
- water molec
- diethyl ether can be used as ?
- medical anesthetic
-
IUPAC
ethers are named as? - alkoxyalkanes
-
IUPAC ethers
smaller chain is? - alkoxy
-
IUPAC
ethers
larger chain? - is named as suffix
- Common naming of ethers use?
- alkyl alkyl ethers
-
methoxyethans
common name would be? - ethyl methyl ether
- oxirane is also called?
- epoxide
- name 3 cyclic ethers?
-
oxirane
oxyethane
oxacyclopentane - oxacyclopentane is also called?
- tetrahydrofuran
- smaller rings have more _____________, making them less stable
- angle strain
-
t or f
ethers do hydrogen bonding - f. they dont have hydrog attach to O
-
ethers bp
are ? - similar to alkanes
-
ethers
solub in water? -
only slightly sol
inert to most organic reag - metal alkoxides w prim alkyl halides or tosylate will make?
- ethers
-
williamson ether synth
makes ethers from? - metal alkoxides w prim alkyl halides or tosylates
-
williamson ether synth
metal alkoxides act as? - nucleophiles
-
williamson ether synth
acts via a ___________ mechanism - SN2
-
williamson ether synth
since its SN2 you need? -
a strong nucleophile (like alkoxide)
unhindered substrate (not bulky or highly subst) -
williamson eth synth
the substrate cant be highly substituted but the attacking alkoxide? - can be highly substituted
-
t or f
williamson ether synth
can also be used w phenols - t
-
williamson eth synth
why do you only need mild react condit? - bec the phenol is more acidic
- cyclic ethers are prepared via ______________ mechanism
- Sn2 internal displacement
- to make a cyclic ether, the _________ and the __________ are part of the same molecule
-
nucleophile
leaving gr - oxidat of an alkene with _________ will produce a oxirane
- peroxy acid like mcpba
- RCOOOH is a?
- peroxy acid
- mcpba is a?
- peroxy acid
- MCPBA stands for?
- m-chloroperoxybenzoic acid
- alkene + mcpba will make?
- an oxirane
-
making a cyclic ether
internal sn2 react
why is this favored? - bec the nucleoph and leaving gr are foced into high conc w each other bec they are on the same molec
-
in air
ethers react w O2 to form? -
peroxides
ROOR - ROOR is the formula for?
- peroxides
- ethers + ? will form peroxides
- O2
- cleavage of straight chain ehters needs?
-
vigorious condit
high temp
w HBr and HI -
cleavage of an ether
is started by? - protonation of ether oxygen
-
cleavage of an ether
why do you need to protonate the ether oxy? - bec otherwise the leaving gr is alkoxide which is strongly basic and a bad leav gr
-
cleav of an eth
ether will bec ? - it will split and end up as 2 alkyl halides
- what reagent do you need to cleave an ether?
- high temp, HBr, HI
-
cleav of an ether with high temp , HBr, HI
makes? -
an alkyl halide and an alcohol
the alcohol w furth react and make anoth alkyl halide -
cleavage of a straight ch ether is
a.acid
b.base catalyzed - a. acid
-
t or f
cleavage of cyclic ethers can be acid or base catalyzed - t
- epoxides easily undergo what kind of react?
- Sn2
- why do epoxides easily undergo SN2 react?
- bec they are highly strained
- epoxide SN2 react can be catalyzed by ________ or _____________
- acid or base
-
epoxide
asymmetrical epoxide
which carbon is nuclephilically attack? in pres of acid? - the more subst c
-
epoxide. in pres of base
which c is nucl att? - the least subs c
- base catal cleav has the most ____________ charact
- SN2
-
epoxid cleav
which catal react has most SN2 charact?
acid or base - base
-
cleav of epoxide
acid catal has some _________- charact - SN1
-
epoxide cleav
acid protonates the epox O and makes it? - a better leaving gr. this gives the c a bit of a posit ch.
-
acid cat cleav of epox
protonation of O makes the carbons? - a little bit positive
- key react of ethers?
-
1. epoxide format
2. SN1 AND sn2 REACT