09.02.2013 Views

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

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

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

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

HO<br />

MeO2C<br />

Br<br />

"N-exo"<br />

O<br />

O O<br />

MeO2C<br />

105<br />

OH<br />

OH<br />

N<br />

O O<br />

O<br />

−<br />

+<br />

N<br />

O<br />

N<br />

O O<br />

108<br />

−<br />

+<br />

HO<br />

104<br />

Scheme 2.42<br />

OH<br />

O O<br />

SYNTHESIS OF NITRONES 167<br />

N OH<br />

OH<br />

i ii<br />

v<br />

MeO 2C<br />

O O<br />

107<br />

O<br />

iv<br />

Br<br />

"N-endo"<br />

MeO2C<br />

O<br />

N<br />

HO<br />

−<br />

+<br />

106<br />

O<br />

O O<br />

iii<br />

O O<br />

(i) NaBH 4,MeOH, 0°C, 1h; (ii) NaIO4, Bu t OH, H2O, 25°C; (iii) Ph3P=CHCO2Me,<br />

PhCOOH (cat.), CH 2Cl2, reflux, 18 h; (iv) PDC, molecular sieves 3 Å (powder), dry<br />

AcOH, CH 2Cl2, 25°C, 30 m<strong>in</strong>; (v) NH2OH•HCl, NaHCO3, MeOH, 25°C, 12 h.<br />

Scheme 2.43<br />

OH

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!