Oxygen Containing Reactions

Question 1

What are the good SN2 leaving groups to know for the MCAT?

Answer 1

water
I-, Br-, Cl-
Acetate
Tosylate ion (-OTs)
Mesylate ion (-OMs)

Question 2

What type of solvent does SN2 favour?

Answer 2

polar aprotic

Question 3

What are 6 common polar aprotic solvents to remember for the MCAT?

Answer 3

acetone
ether
DMSO
DMF
THF
HMPA

Question 4

Which reaction yields a racemic mixture?

a) SN1
b) SN2

Answer 4

a) SN1

Question 5

What is first order kinetics?

Answer 5

rate of the reaction depends only on the concentration of the substrate but occurs over 2 steps

rate = k[substrate]

Question 6

Which reaction shows first order kinetics?

a) SN1
b) SN2

Answer 6

a) SN1

Question 7

Does the nucleophile affect the rate of SN1 reactions? Explain.

Answer 7

NO –> nucleophilic attack occurs after the rate-limiting step (carbocation formation)

Question 8

What type of solvent favours SN1 reactions?

Answer 8

polar protic solvents

Question 9

Give an example of a polar protic solvent.

Answer 9

NaOH

anything that can form hydrogen bonds

Answer 10

Determining structure of a given molecule

Question 11

what reagents and solvents are needed for the preparation of alkyl halides from a tertiary alcohol

Answer 11

HCl, HBr and HI - reagents

diethyl ether - solvent

Question 12

is the preparation of alkyl halides from an alcohol a Sn1 or Sn2 reaction

Answer 12

Sn1

Question 13

what is the general reaction of an ether in the presence of a strong acid

Answer 13

ether + strong acid => alkyl halide + alcohol

Question 14

what are the seven carbonyl compounds

Answer 14

aldehyde, ketone, carboxylic acid, acyl chloride, anhydride, ester and amide

Question 15

true or false - aldehydes and ketones undergo nucleophilic addition

Answer 15

true

Question 16

true or false - a primary alcohol can be oxidized into a aldehyde but not a carboxylic acid

Answer 16

false - it can be oxidized into both

Question 17

what is the reagent used to oxidize a primary alcohol into a aldehyde

Answer 17

PCC

Question 18

what reagent is needed to oxidize a aldehyde into a carboxylic acid

Answer 18

Tollen’s reagent - Ag(NH3)2

Question 19

what reagent is used to oxidize a primary alcohol straight into a carboxylic acid

Answer 19

KMnO4, Jones reagent and H2CrO4

Question 20

what does a secondary alcohol oxidize into

Answer 20

a ketone

Question 21

true or false - tertiary alcohols undergo oxidation

Answer 21

false - they do not

Question 22

what reagents are needed to reduce an aldehyde and ketone and what are the products

Answer 22

sodium borohydride and ethanol followed by an acid workup - the products are primary and secondary alcohols

Question 23

what reagents are needed to reduce a carboxylic acid and ester to a primary alcohol

Answer 23

lithium aluminum hydride/diethylether, followed by an acid workup

Question 24

what is the product of a reaction between an aldehyde/ketone and an alcohol

Answer 24

hemiacetal

Question 25

true or false - alpha hydrogens to a carbonyl are basic

Answer 25

false - they are acidic

Question 26

what are the two ways an enolate anion can accept a proton

Answer 26

1. accepts a proton in its carbanion forming a ketone

2. accepts a proton forming an enol

Question 27

how does enolates react

Answer 27

through base catalyzed alpha substitution