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

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

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256 NITRONES: NOVEL STRATEGIES IN SYNTHESIS<br />

BnO<br />

O<br />

BnO OH<br />

O<br />

a BnO<br />

BnO<br />

BnO<br />

BnO<br />

OH OBn<br />

OBn<br />

N<br />

S<br />

OBn N(OH)Bn<br />

c<br />

*<br />

OH OBn<br />

BnO<br />

351<br />

N<br />

OBn NHBn<br />

Bn<br />

N<br />

OBn<br />

S<br />

88%<br />

b<br />

75%<br />

BnO<br />

BnO<br />

BnO<br />

BnO<br />

OH<br />

OH OBn<br />

N Bn<br />

N<br />

BnO<br />

S<br />

BnO<br />

N(OH)Bn<br />

OBn<br />

Bn +<br />

N<br />

−<br />

O<br />

OBn<br />

N<br />

OBn NHBn<br />

352a (8%) 352b (78%)<br />

d<br />

70%<br />

a: BnNHOH, MgSO 4, CH2Cl2, r.t., 48 h.<br />

b: 2-lithiothiazole, Et2O, −78 °C, 6 h.<br />

c: (AcO)2Cu, Zn, AcOH, H2O, 70 °C, 1 h.<br />

d: Tf2O, pyrid<strong>in</strong>e, 40 °C, 30 m<strong>in</strong>.<br />

+<br />

d<br />

65%<br />

353a 353b<br />

Scheme 2.153<br />

N<br />

OBn<br />

S<br />

S<br />

350

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