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

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Table 2.13 Addition of organolithium compounds to nitrone 361<br />

O N O<br />

361<br />

RM<br />

1. THF/−40°C<br />

2. HCl/MeOH<br />

3. TMSNCO<br />

NITRONE REACTIONS 259<br />

Entry RM Product<br />

Yield (%)<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

7<br />

+ −<br />

O<br />

N<br />

N<br />

S<br />

S<br />

−Li<br />

S<br />

S<br />

+<br />

−Li<br />

S<br />

S<br />

−Li<br />

−Li<br />

−Li<br />

−Li<br />

−<br />

Li<br />

O<br />

N<br />

N<br />

S<br />

O<br />

R<br />

362<br />

OH<br />

N NH2<br />

S<br />

O<br />

OH<br />

N NH2<br />

S<br />

S<br />

OH<br />

N NH2<br />

S<br />

S<br />

O<br />

O<br />

N<br />

OH<br />

N<br />

OH<br />

OH<br />

N NH2<br />

1,6-dioxa-2,9-diazaspiro [4.4] nonanes (369) <strong>and</strong> (370). Compound (369) undergoes<br />

further transformation <strong>in</strong>to oxazetid<strong>in</strong>e (371) (Scheme 2.159) (599).<br />

The reaction of lithiated 2-alkyl-2-oxazol<strong>in</strong>es with nitrones enables stereoselective<br />

<strong>and</strong> enantioselective syntheses of 5-isoxazolid<strong>in</strong>ones, which are used<br />

as precursors of β-am<strong>in</strong>o acids. Highly enantiomerically enriched 5-izoxazolidonones<br />

<strong>and</strong> β-am<strong>in</strong>o acids of <strong>in</strong>verse conÞguration can be generated by simply<br />

chang<strong>in</strong>g the chirality of the <strong>in</strong>itial 2- isopropyl-2-oxazol<strong>in</strong>e (600).<br />

N<br />

OH<br />

O<br />

O<br />

NH2<br />

O<br />

OH<br />

N<br />

NH 2<br />

NH 2<br />

O<br />

NH 2<br />

36<br />

25<br />

28<br />

30<br />

34<br />

24<br />

25

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