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Nitrile Oxides, Nitrones, and Nitronates in Organic Synthesis : Novel ...

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144 NITRONES: NOVEL STRATEGIES IN SYNTHESIS<br />

Table 2.2 Oxidations of hydroxylam<strong>in</strong>es with MnO2<br />

Hydroxylam<strong>in</strong>es Reaction<br />

time (h)<br />

N<br />

OH<br />

Ph N Ph<br />

O<br />

OH<br />

HO<br />

O<br />

O O<br />

N<br />

O<br />

O O<br />

O<br />

BnO<br />

N<br />

HO<br />

N<br />

OH<br />

N<br />

OH<br />

N<br />

OH<br />

Ph<br />

Ph<br />

2<br />

12<br />

<strong>Nitrones</strong> Yield (%)<br />

N<br />

O<br />

Ph N Ph<br />

O<br />

O<br />

O<br />

O<br />

O O<br />

N<br />

Ph<br />

90<br />

93<br />

96<br />

12 O<br />

O O<br />

96<br />

O<br />

N<br />

O<br />

N<br />

O<br />

5:1<br />

OBu t OBu t OBu t<br />

OBn<br />

N<br />

O<br />

BnO<br />

7:1<br />

O O O O<br />

N<br />

OH<br />

2<br />

2<br />

2<br />

2<br />

2<br />

+<br />

−<br />

+<br />

−<br />

N<br />

O<br />

N<br />

O<br />

+<br />

+<br />

Ph<br />

N<br />

+ +<br />

−<br />

O<br />

N<br />

O<br />

OBn<br />

−<br />

+ +<br />

−<br />

+<br />

−<br />

+<br />

−<br />

−<br />

92<br />

85<br />

95<br />

91

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