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

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158 NITRONES: NOVEL STRATEGIES IN SYNTHESIS<br />

HC<br />

O<br />

N<br />

N<br />

OH<br />

BrH2C O<br />

+<br />

N<br />

N<br />

OH<br />

Bu t NHOH<br />

MeOH<br />

Bu t NHOH<br />

MeOH<br />

O<br />

N<br />

O<br />

N<br />

N<br />

N<br />

OH<br />

+ O<br />

N<br />

Bu t NHOH<br />

MeOH<br />

Br2HC + O<br />

N<br />

77 79<br />

78<br />

N<br />

OH<br />

75 76<br />

−<br />

R CN<br />

80a<br />

OP<br />

80a–g<br />

OTBS<br />

CN<br />

i<br />

R<br />

+<br />

−<br />

OP<br />

+<br />

−<br />

Scheme 2.27<br />

a: R = C6H5, P = TBS;<br />

b: R = C 6H5, P = MIP;<br />

c: R = 4-Cl-C 6H 4, P = MIP;<br />

d: R = 4-MeO-C 6H4, P = MIP;<br />

e: R = 4-MeO-C 6H4, P = TBS;<br />

f: R = propenyl, P = TBS;<br />

g: R = 5-Me-furanyl, P = TBS.<br />

N Al(i-Bu) 2 R<br />

−<br />

R<br />

ii<br />

OP<br />

OP<br />

O<br />

N<br />

iii<br />

81a–g<br />

(i) DIBAL; (ii) MeOH, (iii) N-benzylhydroxylam<strong>in</strong>e<br />

Scheme 2.28<br />

OTBS<br />

i ii<br />

R<br />

N<br />

MgX<br />

a: R = CH 3; b: R = n-C3H11.<br />

(i) RMgX, (ii) MeOH, (iii) N-benzylhydroxylam<strong>in</strong>e<br />

Scheme 2.29<br />

+<br />

−<br />

82a–b<br />

OTBS<br />

R<br />

NH<br />

OTBS<br />

iii<br />

O<br />

N<br />

+<br />

R<br />

−<br />

N<br />

OH<br />

−<br />

NH

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