Table 5.
entry | R3b | oxidant | solvent | 90 | 91 | 92 | 74 | 87 |
---|---|---|---|---|---|---|---|---|
1c,d | 88 | CAN | CH3CN | 24% | nde | nd | nd | 3% |
2 f | 88 | 94 | PhH | <5% | nd | nd | 28% | 5% |
3 g | 89 | 94 | CH2Cl2 | 26% | nd | <5% | 15% | <5% |
4 b | 89 | CAN | CH3CN | 17% | 6% | 10% | 8% | 8% |
5 f | 89 | 94 | PhH | 12% | 26% | <5% | 15% | 36% |
Isolated yields.
88: R3 = t-Bu(CH3)2; 89: R3 = (CH3)3.
CAN (2.0 equiv), sodium bicarbonate (20 equiv), CH3CN, –35 °C.
The α-nitrodiazofluorene 93 was obtained in 14% yield.
none detected.
Mn(hfacac)3 (94, 1.20 equiv), PhH, 24 °C.
Mn(hfacac)3 (94, 1.20 equiv), CH2Cl2, 24 °C.