Angewandte Fluororganische Chemie: Synthese ... - Fluorine
Angewandte Fluororganische Chemie: Synthese ... - Fluorine
Angewandte Fluororganische Chemie: Synthese ... - Fluorine
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
X-Ray Structures of the cis and trans Isomers<br />
183 pm<br />
F<br />
F<br />
F<br />
162 pm<br />
F<br />
F<br />
S<br />
F<br />
F<br />
O h<br />
E A<br />
94.4 kcal . mol -1<br />
160 pm<br />
C1-S1-C7: 97.4°<br />
F<br />
F<br />
F<br />
F<br />
S<br />
F<br />
F<br />
D 3h<br />
-F- +F- "fluorophilic" catalyst<br />
F + F +<br />
F<br />
S E<br />
F<br />
A F S F<br />
F<br />
F F<br />
D 3h<br />
6.4 kcal . mol -1<br />
C 4v<br />
162 pm<br />
182 pm<br />
“Fluorophilically” Catalyzed Isomerization:<br />
Proposed Mechanism<br />
cis/trans (85/15)<br />
O2N F<br />
S<br />
+<br />
NO2 F F<br />
The trans-Tetrafluorosulfuranyl Bridge<br />
• The octahedral geometry of hypervalent sulfur fluorides<br />
allows the design of a novel linear bridge element which<br />
is possibly suitable for liquid crystals and other materials<br />
• The synthesis of a mixture of the bis(aryl)tetrafluorosulfuranyl<br />
isomers is conveniently accomplished by direct<br />
fluorination of the corresponding deactivated thioether<br />
cat. BF 3 . Et2 O, CH 2 Cl 2 ,<br />
room temp.<br />
O N 2 S<br />
NO2 F F<br />
trans<br />
P. KIRSCH: <strong>Angewandte</strong> fluororganische <strong>Chemie</strong>: <strong>Synthese</strong>, Pharmazeutika, Flüssigkristalle 50<br />
BF 4 -<br />
• “Fluorophilic” catalysis allows the isomerization of the bent<br />
cis-isomer to the desired linear trans-isomer via the<br />
bis(aryl)trifluorosulfuranonium ion as probable intermediate<br />
“Fluorophilically” Catalyzed Isomerization<br />
87%<br />
F<br />
F<br />
?<br />
liquid crystals
Change language