Table 6.
The influence of pressure on trans‐3 synthesis.[a]
|
Entry |
Catalyst |
T [°C] |
p [bar][b] |
t [h] |
Conv. [%][c] |
Selectivity trans‐3 [%] |
trans/cis 3 |
|---|---|---|---|---|---|---|---|
|
1 |
A+[Bu4N]Br |
140 |
75 |
4.5 |
68 |
76 |
1:0 |
|
2 |
A+[Bu4N]Br |
140 |
60 |
4.5 |
62 |
79 |
1:0 |
|
3 |
A+[Bu4N]Br |
140 |
30 |
4.5 |
65 |
55 |
1:0 |
|
4 |
A+[Bu4N]Br |
140 |
20 |
4.5 |
45 |
35 |
1:0 |
|
5 |
A+[Bu4N]Br |
140 |
1[d] |
4.5 |
16 |
25[e] |
1:0 |
[a] Reaction conditions: trans‐2 (2.16 mmol) (see the Supporting Information IVc), A (2 mol %), [Bu4N]Br (3 mol %), biphenyl (10 mol %) as an internal standard, stirrer speed 300 rpm. [b] Pressure of CO2 at 40 °C. [c] Determined from quantitative 1H NMR spectroscopy. [d] Atmospheric pressure of air. [e] Low concentration of product; main side products identified as 20 and 21 by GC‐MS.