Table 1.
entry | T (°C) |
X (equiv) |
time (h) |
Y (%) |
yield of 3ab (%) |
ratio of 3a/4ab |
---|---|---|---|---|---|---|
1c | 115 | 2 | 2 | 10 | 51 | 1.1 |
2 | 115 | 2 | 1 | 10 | 76 | 5.5 |
3 | 80 | 2 | 1 | 10 | 81 | 7.2 |
4 | 60 | 2 | 2 | 10 | 79 | 8.8 |
5 | 60 | 1 | 2 | 10 | 67 | 9.3 |
6 | 45 | 2 | 24 | 10 | 74 | 10.5 |
7 | 45 | 1 | 24 | 10 | 74 | 10.3 |
A mixture of 0.1–0.2 mmol 1a, 0.1 mmol 2a, 0.225 mmol PhNNPh, 0.0025–0.01 mmol (THF)3TiI2(NPh), and 0.01 Ph3CH (internal standard) in 0.5 mL of CF3Ph were heated at desired temperature and time.
Yield and selectivity are determined by 1H NMR and reported with respect to 2a.
Reported in ref 8 with [py2TiCl2(NPh)]2 as catalyst.