Table 1.
Optimization of the glycosylation conditions with donors 9 and 10 and acceptor 13. The concentration (C) is the concentration of the donor in DCM as solvent. Activators were used in 0.1 equivalent relative to the donor and the reactions were carried out at 0.2 mmol scale.
|
| ||||||
|---|---|---|---|---|---|---|
|
entry |
donor |
C (M) |
T (°C) |
activator |
11 (%) |
12 (%) |
|
1 |
9 |
0.1 |
−50 |
TMSOTf |
34 |
23 |
|
2 |
9 |
0.1 |
−50 |
TfOH |
n.d. |
0 |
|
3 |
9 |
0.1 |
−50 |
TBSOTf |
12 |
39 |
|
4 |
9 |
0.2 |
−50 |
TBSOTf |
48 |
17 |
|
5 |
9 |
0.1 |
−40 |
TBSOTf |
12 |
60 |
|
6 |
10 |
0.1 |
−50 |
TMSOTf |
– |
32 |
|
7 |
10 |
0.1 |
−50 |
TfOH |
– |
53 |
|
8 |
10 |
0.1 |
−50 |
TBSOTf |
– |
56 |
|
9 |
10 |
0.2 |
−50 |
TBSOTf |
– |
23 |
|
10 |
10 |
0.1 |
−40 |
TBSOTf |
– |
48 |
