Ketones and Aldehydes - Chp 18 Flashcards
Which is weaker regarding aromatic substitution reactions? Halogens or CH3?
Halogens
2R-C=O (or C=O) group is named…
oxo
The C=O bond of ketones is ______ (longer/shorter), ________ (stronger/weaker) and more ________ (less/more polar) than the C=C bond of alkenes
shorter; stronger; more polar
As the number of R groups around the carbonyl carbon (C=O) increases, the reactivity of C=O __________ (increases/decreases).
decreases
Increasing steric hindrance _________ (increases/decreases) reactivity towards nucleophiles.
decreases
Nomenclature: For aldehydes you add an ____ suffix.
-al
ex. 2-chloropentanal
Nomenclature: If CHO is bonded to a ring, you name the ring and add _____________.
carbaldehyde
List order of priority.
alkane
carboxylic acids
alcohols
amides
alkyl halides
ketone
alkene
esters
alkyne
aldehydes
ether
carboxylic acids
esters
amides
aldehydes
ketone
alcohols
alkene
alkyne
alkane
ether
alkyl halides
Nomenclature: OH group is named _______.
hydroxy
Nomenclature: For ketones you add an ____ suffix.
“one”
ex. acetone
Compounds that contain both a C-C double bond and a ketone are named as ________.
enones
Compounds that contain both a C-C double bond and an aldehyde are named as ________.
enals
What is a benzoyl group?
Benzene + C=O
Name this group. CHO
methanoyl or formyl
CH3C=O with a benzene is named what?
Acetophenone
Which has a higher b.p? Ketone or aldehyde?
Ketone
Why is the b.p of ketone and aldehyde lower than alcohols?
They can’t H bond to each other.
PCC/Swern/DMP reacting with alcohols forms what?
An aldehyde.
Alkene reacting with (1) O3 (2) (CH3)2S forms what?
A cleavage of the alkene (aldehyde + ketone) and (CH3)2S=O
What reagents are used in the ozonolysis of alkenes?
(1) O3
(2) (CH3)2S
Alkyne reacting with Hg2+, H2SO4 and H2O forms what?
A methyl ketone (CH3-C=O)
What reagents are used in the hydration of alkynes?
Hg2+, H2SO4 and H2O
or
(1) Sia2BH and (2) H2O2, NaOH
Alkyne reacting with (1) Sia2BH and (2) H2O2, NaOH forms what?
An aldehyde.
A Grignard or organolithium reagent attacking the carbon of a nitrile forms what?
A ketone.
Which compound exists to the greatest extent as it hydrates when dissolved in aq solution? Aldehyde or ketone? Does conjugation increase or decrease its extent?
Aldehyde; conjugation increases its extent.
What increase the reactivity toward cyanohydrin formation w/ HCN or KCN and ketones?
Electron-withdrawing groups (ex. halogens).
What reagent can reduce nitriles to aldehydes?
Aluminum hydride
ex. LiAlH4, (i-Bu)2AlH
Give the general formula for a hemiacetal.
OH-C-OR
(C attached with an OH group and an OR group)
Give the general formula for an acetal.
OR-C-OR
(C attached to 2 alkoxy groups)
Oxidizing aldehydes forms what product?
(Easily oxidized to…) carboxylic acids
Which is more reactive? Aldehydes or ketones? Why?
Aldehydes b/c they are more polarized and has less steric hindrance compared to the 2 R groups on ketones.
PCC oxidizes primary alcohols to ________ and secondary alcohols to _______.
aldehydes; ketones
What reagents can oxidize a secondary alcohol to a ketone?
PCC
K2Cr2O7, H2SO4, H2O
Does lithium aluminum hydride reduce both carbonyls if a compound has 2 carbonyl groups?
Yes.
Sodium borohydride (NaBH4) can reduce __________ to _________ (secondary/primary) alcohols and ___________ to _________ (secondary/primary) alcohols.
ketones; secondary; aldehydes; primary
Can LiAlH4 reduce any carbonyl? Explain.
Yes b/c it is a very strong reducing agent. (Difficult to handle)
Raney Nickel (Ni-H2) reacting with a carbonyl forms…
An alcohol group.
What reagent is used in catalytic hydrogenation?
Ni-H2
What reagent are used in Clemmensen reduction?
Zn(Hg), HCl and H2O
Zn(Hg), HCl and H2O reacting with ketones or aldehydes forms…
An alkane. (Reduces carbonyl “twice” by adding Hs.)
What reagents are used in Wolff-Kishner reduction?
N2H4, KOH and heat
What is the hydrazone group?
-C=N-NH2
Carbonyl reacting with N2H4 forms what?
A hydrazone.
