Chem 3580 - Spring 2009
Problem Set 8 - solutions
1. (a) Retrosynthesis
O
CH
3
O
CH
3
O
O
CH
3
O
O
OH
!
O
CH
3
O
O
OEt
!
"
O
O
OEt
O
CH
3
+
!
"
intramolecular
aldol
Decarboxylation
Hydrolysis
Michael
addition
Ethyl acetoacetate
Claisen
CH
3
OC
2
H
5
O
2
Forward synthesis
CH
3
O
O
2
NaOEt (1 equiv)
O
O
O
Claisen
CH
3
O
CH
3
O
O
O
O
CH
3
O
O
O
O
Decarboxylation
CH
3
O
O
NaOH (cat), H
2
O
!
Intramolecular aldol
O
CH
3
Michael Addition
O
CH
3
O
O
O
H
Hydrolysis
Ethyl acetate
can be done in one step (H
3
O
+
, Heat)
Na
+
H
3
O
+
H
3
O
+
!
(b) Retrosynthesis
O
O
OH
O
O
O
O
O
O
O
+
Br
H
3
C
O
O
CH
3
O
O
decarboxylation
alkylation
hydrolysis
intra-molecular
Claisen
(Dieckmann)
Forward synthesis
H
3
C
O
O
CH
3
O
O
1. NaOEt (1 equiv)
Intramolecular
Claisen
O
O
O
CH
3
Br
O
O
CH
3
O
Alkylation of the
enolate
base hydrolysis
(saponification)
followed by
mild
acidic work-up
O
O
H
O
!
Decarboxylation
O
1. NaOH, H
2
O,
!
2. Dilute HCl, 25°C
This
preview
has intentionally blurred sections.
Sign up to view the full version.
2.
O
O
!
Br
O
EtO
O
O
Ethyl acetoacetate
!

This is the end of the preview.
Sign up
to
access the rest of the document.
- Spring '09
- JONNJARDARSON
- Mole, intramolecular Aldol, ! 2
-
Click to edit the document details