Answers to MiniQuiz 4:
α-bromoethylbenzene
Quartet 1:3:3:1 !
Score: 2*/2
α-dibromoethylbenzene: one singlet and groups of aromatics
Your Questions ??
Today:
• “Esterification”
• Grignard reactions
• MiniQuiz
• Next Tuesday, March 10: Conclusion of Grignard.
• MiniQuiz on today’s class
• Following Tuesday 3/17:
Your questions. Introduction to Unknowns.
Midterm 2:10 – 4pm in your lab
(5 Problems. Total: 100 Pts.)
Do Sample Midterms (in eres file; password!).
Review/study labs with calculations and problems and our lab
lectures.
Methyl Benzoate Synthesis
An equilibrium! Keq=3.0
Our Esterification Procedure
1. What are the advantages of "boiling under reflux”?
2. What was the purpose of each of the following
extraction steps:
1. rinsing with water
2. then extracting with sodium bicarbonate solution
3. extracting with sat. sodium chloride solution?
3. In our extraction with ether, which was the organic
layer, top or bottom?
4. What would the H-NMRs of methyl benzoate and of
benzoic acid look like?
Grignard
•
•
What is a "Grignard reagent“?
•
Properties of Grignard reagents?
Which products do you obtain from the reaction of a
Grignard reagent with a carbonyl group followed by
hydrolysis?
•
from an aldehyde…
from a ketone…
from an ester… ?
•
What type of a reaction is it ….?
•
Reaction of RMgX with water…?
Victor Grignard found that, in
the presence of ether,
magnesium reacts with alkyl
and aryl halides at room
temperature to form
organomagnesium compounds.
For this discovery he was
awarded the 1912 Nobel Prize
in Chemistry.
RMgX – Ether Complex
• Grignard reagents are metal-organic compounds. Other
examples of metal-organic compounds? Are there any in nature?
CH
CH 2 CH 3
H3 C
CH 2 CH 3
N
N
Mg
H3 C
N
N
CH 3
H
H H
CH 3 OOC
O
O
O
Chlorophyll a
Grignard
Our multistep synthesis of triphenyl methanol, starting
with the synthesis of our Grignard reagent:
DRY!
DRY!
Grignard
Adduct
Write the structure of the product obtained if our Grignard
reagent reacts with
a) water
b) methanol
c) benzoic acid
d) carbon dioxide
e) acetone
f) formaldehyde
TLC
Thin Layer Chromatography is an example of
chromatography.
•Do you know other types of chromatography?
•What is common to all types of chromatography?
TLC
What is the moving phase, the stationary phase in
our TLC?
What type of information do we expect from our
TLC?
Next Tuesday:
Conclusion of Grignard.
MiniQuiz on today’s class!
MiniQuiz 5 Problems:
1) Draw the structure of a diene (your choice)
that would work well in a Diels-Alder
reaction.
2) Draw the structure of a dienophile that
would work well in a Diels-Alder reaction.