Chapter 6- Aldehydes and Ketones I: Electrophilicity and Oxidation-Reduction

Question 1

carbonyl in reactions

Answer 1

can be nucleophile (in condensation reactions) or an electrophile (in nucleophilic addition reactions)

Question 2

carbaldehyde

Answer 2

aldehyde that is attached to a ring

Question 3

physical properties or aldehydes and ketones

Answer 3

governed by presence of carbonyl group.

dipole moment increases boiling point of aldehydes and ketones relative to alkanes. alcohols still have a higher boiling point than aldehydes and ketones tho due to the hydrogen bonding.

Question 4

do aldehydes or ketones have more steric hindrance

Answer 4

aldehydes are more reactive toward nucleophiles than ketones because they have less steric hindrance

Question 5

most tested and common electrophile on MCAT and explain.

Answer 5

carbonyl carbon. dipole moment is due to the oxygen which is more electronegative b.c its pulling electrons away from the carbon making the carbon more electrophilic thus a good target for nucleophiles.

Question 6

whats the furthest a secondary alcohol can be oxidized to

Answer 6

ketone

Question 7

in the formation of hemiacetals/ hemiketals and acetals/ ketals list the nucleophile and electrophile

Answer 7

hemiacetals/hemiketals- alcohol (N), carbonyl carbon (E)

acetals/ketals- alcohol (N), carbocation carbon (E)

Question 8

imine

Answer 8

compound with a nitrogen double bonded to a carbon

Question 9

enamine

Answer 9

contain both a double bond and a nitrogen-containing group. (imines naturally tautomerize to this)

Question 10

hydrogen cyanide

Answer 10

HCN, classic nucleophile on the MCAT. acidic due to triple bond and an electronegative nitrogen atom.

in a reaction with HCN, CN- is the nucleophile and the carbonyl carbon is the electrophile

Question 11

cyanohydrins

Answer 11

reactions with HCN and aldehydes/ ketones produce these once the oxygen has been reprotonated

Question 12

when an aldehyde or ketone is reacted with one or two equivalents of alcohol, what occurs?

Answer 12

one- hemiacetal, hemiketal

two- acetal, ketal

Question 13

when you see hydride reagents like lithium aluminum hydride (LiAlH4) and sodium borohydride (NaBH4) what is typically happening

Answer 13

aldehydes and ketones are undergoing reduction to form alcohols

Question 14

what forms when water attacks a carbonyl carbon

Answer 14

a geminal diol forms