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

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

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696 NITRONATES<br />

R<br />

497<br />

N<br />

TBS – SiMe 2Bu t<br />

OTBS<br />

498<br />

a<br />

b<br />

c<br />

d<br />

TBDPSO<br />

500 V-70<br />

OTBS<br />

N<br />

Ph<br />

500<br />

R<br />

OTBS<br />

OTBS<br />

H**<br />

H<br />

OTBDPS<br />

R′ I /(Bu3Sn)2<br />

hν<br />

OSiBut • Ph2<br />

R′<br />

PhSO *<br />

2<br />

CH2CO2Me CH2CO2Et CH2SO2Ph 1,2-Ph-transfer<br />

SiBut • (OPh)Ph<br />

R′<br />

Scheme 3.258<br />

EtO2CCH2I; V-70<br />

CH2Cl2, 30οC 501<br />

R<br />

498a–d<br />

N OTBS<br />

EtO 2CCH 2CH 2CH=CHCHO<br />

Yield%<br />

50<br />

58<br />

65<br />

62<br />

EtO<br />

O<br />

499c 93%<br />

* PhSO2Br as precursor<br />

** (Me3Sn) 2 <strong>in</strong>stead (Bu3Sn) 2<br />

501<br />

ISiBu<br />

V-70 – 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile)<br />

t TBDPS – SiBu (OPh)Ph<br />

tPh2 RI<br />

NOTBDPS<br />

500 + RI<br />

Ph<br />

502<br />

R<br />

R Yield 502 %<br />

PhSO 2CH 2<br />

Et2NCOCH2<br />

NCCH 2<br />

EtOCOCH(Me)<br />

(EtOCO) 2CH*<br />

61<br />

63<br />

68<br />

72<br />

75<br />

* (EtOCO) 2CHBr as precurssor<br />

Scheme 3.259<br />

Ph<br />

N<br />

83%<br />

OTBDPS<br />

•<br />

R• R<br />

Ph<br />

N<br />

OTBDPS<br />

500<br />

OTBDPS

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