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

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504 NITRONATES<br />

Ha<br />

R′<br />

Hb<br />

R′′<br />

O N<br />

O<br />

Hb<br />

H a<br />

Hi<br />

R′′<br />

R′ Hx<br />

O N<br />

A B<br />

Chart 3.7<br />

Table 3.12 14 N<strong>and</strong> 15 N resonances for nitronates<br />

δ=N(O)O−<br />

Entry Nitronate ( 14 N, ppm) Hz Ref. Notes<br />

1 MeCH=N(O)OSiMe3 −83 ± 5 270 ± 20 277<br />

2 Me2C=N(O)OSiMe3 −97 ± 10 550 ± 30 277<br />

3 MeC(NO2)=N(O)OSiMe3 −74 ± 8 350 ± 50 272,277 −12 ± 2<br />

(Δ ≈ 100 Hz)–NO2<br />

1 J( 13 C, 15 N) = 21.4<br />

<strong>and</strong> 39.7 Hz<br />

Table 3.13 29 Si <strong>and</strong> 11 B resonances for nitronates<br />

Entry Nitronate δ ( 29 Si) ppm δ ( 11 B) ppm Ref<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

MeCH=N(O)OSiMe3<br />

Me2C=N(O)OSiMe3<br />

(MeO2C)2C=N(O)OSiMe3<br />

Me2C=NOSiMe3<br />

(MeO2C)2C=NOSiMe3<br />

[Me2C=N(O)OBEt2]2<br />

22.6<br />

21.1<br />

32.7<br />

21.2<br />

33.8<br />

12.0<br />

277<br />

277<br />

277<br />

267<br />

277<br />

229<br />

7<br />

O<br />

15.8 230<br />

(MeO2C) 2C N<br />

O<br />

BEt 2<br />

the N - oxide oxygen atom, by the functional group, or by on external complex<strong>in</strong>g<br />

agent (pyrid<strong>in</strong>e) (<strong>in</strong> addition, see Tables 3.10 <strong>and</strong> 3.11).<br />

3.3.3. Character of Bonds <strong>in</strong> the Nitronate Fragment (X-ray <strong>and</strong><br />

Calculation Data)<br />

<strong>Nitronates</strong> have not been adequately studied by X-ray diffraction <strong>and</strong> calculation<br />

methods. Characteristic X-ray diffraction data for different types of nitronates are<br />

given <strong>in</strong> Table 3.14.<br />

O

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