12: Aldehydes and Ketones (Part 1) Flashcards
The Wittig reaction uses a carbon nucleophile, the Wittig reagent, to form?
alkenes
Aldehydes and ketones are also both obtained as products of the ________________ of alkenes
oxidative cleavage
The stronger the intermolecular forces, the __________ the bp or mp
higher
Aldehydes and ketones exhibit _______________ interactions because of their polar carbonyl group
dipole–dipole
C– H bond on the α carbon to a carbonyl group is ________________ than many other C – H bonds
more acidic
In nucleophilic addition, as the number of R groups around the carbonyl carbon increases, the reactivity of the carbonyl compound will?
decrease
these can be reconverted to carbonyl compounds by treatment with base.
cyanohydrins
In nucleophilic addition, as the number of R groups around the carbonyl carbon increases, the ________________ of the carbonyl compound decreases
reactivity
Aldehydes and ketones are also both obtained as products of the oxidative cleavage of?
alkenes
RCHO and RCOR having ≤5 C’s are?
water soluble
Aldehydes and ketones form _________ that react with electrophiles at the α carbon
enolates
this forms 2 new C-C bonds, 1 new σ bond, and 1new π bond— as well as a phosphorus by-product, Ph3P=O (triphenylphosphine oxide).
Wittig reaction
these react with nucleophiles
aldehydes and ketones
this reacts with a base to form a carbanion
C - H bond
this makes aldehydes and ketones susceptible to nucleophilic addition reactions
electrophilic carbonyl carbon
RCHO and RCOR having ________ are water insoluble because the nonpolar alkyl portion is too large to dissolve in the polar H2O solvent
> 5 C’s
The cyano group (CN) of a cyanohydrin is readily hydrolyzed to a ____________ (COOH) by heating with aqueous acid or base
carboxy group
Treatment of an aldehyde or ketone with NaCN and a strong acid such as HCl adds the elements of HCN across the carbon–oxygen π bond, forming a?
cyanohydrin
these are also both obtained as products of the oxidative cleavage of alkenes
aldehydes and ketones
if the reactivity towards nucleophiles increases, the steric hindrance will?
decrease
Aldehydes and ketones exhibit dipole–dipole interactions because of their?
polar carbonyl group
RCHO and RCOR having >5 C’s are ________________
water insoluble
The R groups stabilize the partial charge on the carbonyl carbon of a ketone, making it more _______ and less __________
stable, reactive
these exhibit dipole–dipole interactions because of their polar carbonyl group
aldehydes and ketones
C - H bond reacts with base to form a?
carbanion
RCHO and RCOR are ___________ in organic solvents regardless of size
soluble
these form enolates that react with electrophiles at the α carbon
aldehydes and ketones
how to prepare ketones
- by oxidation of 2-degree alcohols with Cr6+ reagents
- by reaction of acid chlorides with organocuprates
- by Friedel-Crafts acylation
- by hydration of alkyne
In _____________________, as the number of R groups around the carbonyl carbon increases, the reactivity of the carbonyl compound decreases
nucleophilic addition
The two R groups bonded to the ketone carbonyl group make it more crowded, so nucleophilic attack is?
more difficult
RCOR
ketone
RCHO
aldehyde
The _______________ bonded to the ketone carbonyl group make it more crowded, so nucleophilic attack is more difficult
two R groups
this uses a carbon nucleophile, the Wittig reagent, to form alkenes
Wittig reaction
RCHO and RCOR having __________ are water soluble
≤5 C’s
C– H bond on the ___________ to a carbonyl group is more acidic than many other C – H bonds
α carbon
if the reactivity towards nucleophiles decreases, the steric hindrance will?
increase
The Wittig reaction uses a carbon nucleophile, the ____________, to form alkenes
Wittig reagent
how to prepare aldehydes
- by oxidation of 1-degree alcohols with PCC
- by reduction of esters and acid chlorides
- by hydroboration-oxidation of an alkyne
there is no H-Bonding
aldehydes and ketones
