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

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676 NITRONATES<br />

R 3<br />

O −<br />

N<br />

448<br />

R 1<br />

R 2<br />

NO2<br />

c<br />

R 1<br />

R 2<br />

R 3<br />

N O<br />

B<br />

N<br />

R 1 R 2<br />

NOH<br />

445<br />

O<br />

+<br />

b<br />

O<br />

H<br />

O<br />

R 1 R 2<br />

R 3<br />

R 3<br />

−<br />

NO2 DBUH +<br />

C<br />

NOH<br />

NOH<br />

446<br />

Scheme 3.239<br />

a<br />

HON<br />

R 1<br />

R 2<br />

R 3<br />

NO2<br />

R 2 =H B<br />

R 3<br />

d<br />

R 2 NO2<br />

447<br />

NOH<br />

443<br />

R 3<br />

NOH<br />

Table 3.31 C,C-coupl<strong>in</strong>g BENA with anions of primary AN (R 2 = H, catalysis with<br />

F − <strong>in</strong> CH2Cl2)<br />

R 1 R 3 Temp., ( ◦ C) Yield of (443), %<br />

Et Me −78 78<br />

H Me −78 64<br />

Me Me −78 70<br />

(CH2)2CO2Me Me −78 90<br />

CO2Me Me −78 64<br />

CH2CO2Me Me −78 94<br />

CH2CO2Me H −78 88<br />

(CH2)2CO2Me H −100 77 a<br />

Et (CH2)2CO2Me −100 79 b<br />

CH2CO2Me (CH2)2CO2Me −100 84<br />

CO2Me (CH2)2CO2Me −78 78<br />

Me (R 2 =Me) Me −78 52<br />

a rel. (443:447)=8:1;<br />

b rel. (443:447)=7:1

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