Week 7 and 8: ketones and aldehydes

Question 1

why are aldehydes more reactive than ketones

Answer 1

because they have one less r group, meaning they aren’t as good as electron donors.
Also due to steric strain and electronic effects

Question 2

What are the three types of nucleophiles?

Answer 2

Oxygen (hydration reactions)
Hydrogen (hydrides)
Carbon (Grignard reagents)

Question 3

What type of solvent is used with NaBH4?

Answer 3

because it is a mild hydride source it will use EtOH, alcohols

Question 4

What type of solvent is used with LiAlH4?

Answer 4

aprotic solvents, EtO2

Question 5

In the acid-catalyzed hydration reaction, why does the acid make the reaction happen faster?

Answer 5

the protonation makes the carbonyl a better electrophile

Question 6

In the base-catalyzed hydration reaction, why does the base make the reaction happen faster?

Answer 6

The hydroxide is a better nucleophile than water

Question 7

What is formed when simple sugars crystallize to form hemiacetals?

Answer 7

anomers

Question 8

Anomer

Answer 8

cyclic hemiacetal that differ in configuration at the anomeric carbon

Question 9

Anomeric carbon:

Answer 9

this is the carbonyl carbon that is attacked to the aldehdyde/ketone

Question 10

True/False. Anomers will produce unique H NMR spectra

Answer 10

true

Question 11

Why is the anomer with the alcohol group in equatorial more favoured?

Answer 11

because of less steric strain