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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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Me 3SiO<br />

Me3SiO<br />

N<br />

Me3SiON<br />

Me 3Si<br />

H<br />

NC<br />

TfOSi<br />

A<br />

H<br />

NC<br />

583<br />

Me3SiO N<br />

OSiMe 3<br />

NC 589<br />

588<br />

Me3SiO<br />

H<br />

20°C<br />

MeOH/F −<br />

587<br />

Me3SiOH<br />

O<br />

588<br />

O<br />

O<br />

SILYLATION OF NITRO COMPOUNDS AS A PROCESS 721<br />

Me 3Si 2O<br />

OTf<br />

O<br />

Me3Si<br />

Me 3Si<br />

Me 3Si<br />

Me3SiO<br />

OTf<br />

Me3SiN<br />

NC<br />

NC<br />

N<br />

Scheme 3.282<br />

N<br />

B<br />

20°C<br />

20°C<br />

OSiMe3<br />

586<br />

OSiMe3<br />

OSiMe3<br />

584<br />

Me3SiOH 585<br />

H NEt3<br />

OSiMe3<br />

Et3NHOTf<br />

Me3SiO<br />

C<br />

NC<br />

O<br />

CN O<br />

590<br />

NC<br />

591b(E)<br />

591a (Z)<br />

of the trialkylsilyl fragment <strong>in</strong> the result<strong>in</strong>g unstable derivative C. Apparently,<br />

this rearrangement is very sensitive to steric factors due to which the Z isomer<br />

of silylated nitrile (586) is formed stereoselectively. This product can undergo<br />

desilylation with retention of the-cis conÞguration of the C,C double bond. For<br />

example, the carbonyl group can be selectively desilylated (nitrile (590)) by<br />

O

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