Angewandte Fluororganische Chemie: Synthese ... - Fluorine

Te mpe rature
Δε
Δn
140
120
100
80
60
40
20
0
CC P-3F.F ax-fluoro gem-difluoro vinylic fluorine
F
F
I
N
C
6.4 6.8 9.7 10.0
0.079 0.079 0.084 0.109
F
F
Merck KGaA - Liquid Crystal Research
4.2. Polare Endgruppen: Die Trifluormethylgruppe - Synthesemethoden
H 7 C 3
H 7 C 3
CF 3
Δε = 6.8 Δn = 0.054
H 5 C 2
CF 2 CF 2
Δε = 6.2 Δn = 0.054
H 7 C 3
F
F
CF3 H C 7 3
Δε = 16.3 Δn = 0.086 Δε = 23.8 Δn = 0.138
CF 3
H 7 C 3
Δε
Δε = 9.5 Δn = 0.091
F C 3 F
Δε = -7.5 Δn = 0.132
Dr. Peer Kirsch Merck KGaA - Liquid Crystal Research
CF 3
Δn
OEt
F
H 11 C 5
H 7 C 3
F
F
CF 3
Δε = 9.7 Δn = 0.09
F
F
CF 3
CF 3
Δε = 18.2 Δn = 0.137
Ortho-Metallation and Copper-Mediated
“Radical” Trifluoromethylation
H 7 C 3
67%
1. LDA, THF;
-40 o C
2. I 2
20-30%
O
CuI, F 3 CCOOK,
cat. Me 4 NBr,
NMP; 120 o C
H 7 C 3
H 7 C 3
H 7 C 3
C 100 I
T NI = 56.1ºC (extrapol.)
Δε = 16.3 Δn = 0.086
Dr. Peer Kirsch Merck KGaA - Liquid Crystal Research
F
F
F
F
I
CF 3
F
F
D. Pauluth, 1990
P. KIRSCH: Angewandte fluororganische Chemie: Synthese, Pharmazeutika, Flüssigkristalle 42
F
F
F
F
F
F
F
F
Use of Pre-Formed Building Blocks
H 7 C 3
80-90%
O
Cat. TsOH,
toluene; -H 2 O
F 3 CPhBr, BuLi,
THF; -78 o C
H 7 C 3
30-40%
H7C3 1. H2 , 5% Pd-C,
THF
2. Crystallization
H 7 C 3
C 133 I
T NI = 114.3ºC (extrapol.)
Δε = 9.5 Δn = 0.091
Dr. Peer Kirsch Merck KGaA - Liquid Crystal Research
H 7 C 3
H7C3 1. BuLi, KOtBu,
Et2O; -100
F
oC 2. B(OMe) 3 ; -35o 49%
C
3. HCl
64%
1. LDA, THF;
-70 o C
2. I 2 ; -35 o C
H 7 C 3
B(OH) 2
CF 3
CF 3
OH
CF 3
E. Poetsch, 1995
Ortho-Metallation and Copper-Mediated
“Radical” Trifluoromethylation
H 7 C 3
23%
CuI, F 3 CCOOK,
cat. Me 4 NBr,
NMP; 155 o C
H 7 C 3
F
F
F
F
F
F
Dr. Peer Kirsch Merck KGaA - Liquid Crystal Research
CF 3
F
F
3,5-difluorobromobenzene,
cat. Pd(PPh3 ) 4 ,
K2CO3 , H2O, EtOH, H2O;50o 97%
C
C 79 I
T NI = 10.7ºC (extrapol.)
Δε = 23.8 Δn = 0.138
F
F
E. Bartmann, 1994
I