Table 1.
Comparison of bifunctional phosphonium salts in the cycloaddition of CO2 with epoxides.
|
| ||||||
|---|---|---|---|---|---|---|
|
Entry |
Catalyst |
Loading [mol %] |
T [°C] |
t [h] |
Yield[a] [%] |
TON |
|
1 |
3 |
2 |
23 |
24 |
25 |
13 |
|
2 |
5 |
2 |
23 |
24 |
2 |
1 |
|
3 |
6 |
2 |
23 |
24 |
2 |
1 |
|
4 |
7 |
2 |
23 |
24 |
10 |
5 |
|
5 |
8 |
2 |
23 |
24 |
65 |
33 |
|
6 |
7 |
2 |
45 |
6 (24) |
60 (>99) |
30 |
|
7 |
8 |
2 |
45 |
6 (24) |
85 (>99) |
43 |
|
8 |
7 |
2 |
90 |
2 |
89 |
45 |
|
9 |
8 |
2 |
90 |
2 |
96 |
48 |
|
10 |
8 |
5 |
23 |
24 |
>99 |
50 |
|
11[b] |
8 |
5 |
23 |
24 |
71 |
36 |
Reaction conditions: 1.0 equiv. 1 a (1.00 g, 13.9 mmol), 2–5 mol % catalyst, 2–24 h, p(CO2)=1.0 MPa, solvent‐free. [a] Yields were determined by 1H NMR spectroscopy using mesitylene as internal standard. [b] p(CO2)=0.1 MPa. TON: turnover number.