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.

550 NITRONATES<br />

HO<br />

CO 2Me<br />

Ref.<br />

49, 91, 92, 97,<br />

161, 162, 370<br />

Ref.160, 162<br />

COMe<br />

Ref.162<br />

* *<br />

Ref.162<br />

Ph<br />

S R<br />

O<br />

p-Br-C6H4OCO<br />

CO2Et Ref.162<br />

OAc<br />

CO 2Et<br />

Me<br />

Ref.162<br />

CN<br />

Ph<br />

Ref.162<br />

CO2But<br />

Ref.<br />

143,<br />

146<br />

Ref.<br />

49, 91, 92, 97,<br />

371<br />

O Ref.49<br />

O<br />

N<br />

Me<br />

Ref.92, 97,<br />

372<br />

CH2Cl<br />

Ref.162<br />

CHO<br />

Ref.162<br />

Me3SiOH 2COC Ref.372<br />

p-Br-C6H 4<br />

Ref.156<br />

AcO<br />

MeO 2C<br />

MeOC<br />

Ref.162<br />

CO 2Me<br />

PhH 2C CO 2Me<br />

Ref.162<br />

CO2Et<br />

Ref.162<br />

Me<br />

Ref.162<br />

PhH 2COH 2COC SiMe 2Ph<br />

MeO 2C<br />

Ref.162<br />

SiMe 3<br />

Ref.<br />

138,<br />

151,<br />

161<br />

PhCH=CHNO2 Ref.373<br />

"head to head"<br />

SiMe 3<br />

Ref.372<br />

Ref.143<br />

OEt<br />

MeO 2C<br />

CO 2Me<br />

Ref.151<br />

Pr i Me 2SiOC SiMe 2Ph<br />

O<br />

O<br />

O<br />

Ref.162<br />

Ref.49<br />

Chart 3.14 [3 + 2]Reactivity of six-membered cyclic nitronates.<br />

Ref.49,<br />

161, 162<br />

CO 2Me<br />

improved procedure was applied to a series of mono- <strong>and</strong> α,β-disubstituted oleÞns<br />

conta<strong>in</strong><strong>in</strong>g EWG groups (49).<br />

3.4.3.1.5. Attempts to Catalyze [3 + 2]-Cycloaddition of <strong>Nitronates</strong> to OleÞns In<br />

Section 3.2.1.2.2.2, it was noted that [4 + 2]-cycloaddition reactions of nitroalkenes<br />

<strong>and</strong> alkenes proceed much faster <strong>in</strong> the presence of LA. At the same<br />

time, <strong>in</strong> the presence of LA, nitronates can rapidly decompose (49) or undergo<br />

rearrangements (see Section 3.4.2.5.6.). Hence, it is not surpris<strong>in</strong>g that catalysis of<br />

1,3-dipolar cycloaddition reactions of nitronates with alkenes by LA has attracted<br />

little attention until very recent times. An exception is the study by the Japanese

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

Saved successfully!

Ooh no, something went wrong!