Jasmone 1 - ChemistforChrist

Synthesis of JASMONE
O
O
O
(with cat. Stetter reagent)
+
O
BrMg
Br
HO
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+ DMF
(already discussed
see above)
For adding a formyl DMF is the best reagent (Adding the Weinrebamide would more complicated).
O
H OH
O
H OH
SO 2Cl 2
DCC
Me
HN
OMe
O
H Cl
H
O
N
Me
OMe
instable
BrMg
CO + HCl
Historically Formyl groups were added with the help of Orthoesters:
Et Et
O
R MgX
Et O in the presence of :
Heat > 35°C
and evaporate
R MgX
Et
OEt
HC OEt
OEt
Orthoester
the ether
OEt
HC OEt
OEt
Stetter chose to change the orthoester in making
one of the OEt group to a better leaving group a
Phenol (OPh). This facilitates the reaction and it can
be done now at r.t.
OEt
HC OEt
OEt
+ PhOH HC
OEt
OEt
OPh
+ HOEt
Utilisation of mixed othoformiates: Chem. Ber. 1970, 103, 643
Synthesis of Stetter
MgBr
OEt
HC OEt
OPh
O
Jasmone
R
O
H
H
H 3O
O
R
H
OEt
OEt
Highly reactive,
will react immediately
with the grignard
reagent.
R
R MgX
OEt
H
OEt
OEt O
H3O OEt
NaOH
10 mol%
Thiazolium-Salt
O
4
3
O
2
1
O