Chemistry Reference
In-Depth Information
Tab. 4.43.
Synthesis of diaryl ketones with oxalyl chloride [946].
Arene A
Chlorocarbonylation Arene B
Acylation Product
Yield
%
O
30 min, 10
C
14 h, rt
77
O
30 min, 10
C
1h,rt
74
OMe
OMe
O
30 min, 10
C
14 h, rt
68
O
2h,rt
14 h, rt
72
OMe
OMe
O
14 h, rt
5h,rt
70
Cl
Cl
O
e
14 h, rt
14 h, rt
54
Br
MeO
Br
methoxy ketone, often demethylated under Friedel-Crafts conditions [951], could
be prepared in satisfactory yield.
Typical procedure. Symmetrical diaryl ketone [946]:
In a 100-mL round-bottomed
flask with a side-arm, oxalyl chloride (1.05 mL, 12 mmol) was added dropwise over
a period of 5 min to a solution of p-xylene (1.23 mL, 10 mmol) in dichloromethane
(50 mL) at 5
C. Aluminum chloride (1.33 g, 10 mmol) was then added portion-
wise over 5 min to give a yellow suspension. The reaction mixture was allowed to
warm to room temperature and stirred for 1 h, during which time dissolution of
the solid and gas evolution were observed. A second equivalent of p-xylene (1.23
mL, 10 mmol) was then added dropwise over a period of 5 min, and the reaction
mixture was stirred for 13 h at room temperature. It was then chilled in an ice/
water bath, and water (25 mL) was added dropwise over a period of 10 min. The
layers were separated, and the aqueous layer was extracted twice with dichloro-
