Chemistry Reference
In-Depth Information
CO
3
H
acetophenone
benzophenone
cyclohexanone
cyclopentanone
ethylmethyl ketone
phenyl acetate
phenyl benzoate
caprolactone
valerolactone
ethyl acatate
or
SO
4
H
Fig.
8
.49
Esters and lactones from
Baeyer-Villiger oxidations.
R
CH
2
NMe
3
+
-
O
OO
CH
2
Cl
2
R
R
O
Cl
O
O
Fig.
8
.50
Ethers from phenoxide-
exchanged resins.
R
P
R
R
+
OH
R'
OH
O
R'
Fig.
8
.51
Ethers from Mitsunobu
reactions.
DEAD, rt,
symmetric bis(aryl) ethers [149], propranolol [150]
or alkyl aryl ethers [151] (Fig. 8.50).
Other phenyl ethers are obtained through a Mit-
sunobu reaction between a phenol and an alcohol
with polystyrene-triphenylphosphine and in the
presence of diethyl azodicarboxylate (DEAD) [152]
(Fig. 8.51).
Glycosides are obtained with a bromoselenic
reagent obtained by treating polystyrene with
dimethylselenide and butyllithium and then with
bromine: alcohols add to tri-
O
-benzylglycal and give
2-deoxyglycosides [153] after cleavage of the C—Se
bond with Bu
3
SnH/azobisisobutyronitrile (AIBN).
mesylates with fluoride-exchanged resins [154,155]
(Fig. 8.52).
Nucleophilic fluorinations also are possible with
a polystyrene-supported fluoroalkylamine (FAR)
that is stable enough to be stored [156]. Primary,
secondary and tertiary alcohols are converted into
the corresponding fluoroalkanes (Fig. 8.53).
The polymeric equivalent of the pyridine-
poly(hydrogen fluoride) complex also is a hydro-
fluorination agent, obtained from cross-linked
polyvinylpyridine, that performs the fluorination of
secondary and tertiary alcohols and the addition of
HF to alkenes and alkynes [157,158] (Fig. 8.54).
It should be noted that aliphatic tertiary amines
also can give liquid tris(hydrogen fluoride) com-
plexes that are non-fuming, distillable and easy to
handle [159]. The supported analogues could be
obtained with adequate polymeric tertiary amines.
3.13 Fluoro derivatives
Alkyl fluorides are obtained by nucleophilic
substitution reactions of chlorides, bromides and
