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

Table 3.1 The silylation of AN by Et3N/SiX
SYNTHESIS OF NITRONATES 473
The product Yield,
Entry AN SiX Solvent of silylation %% Ref.
1 MeNO2 Me3SiCl C6H6
Me3SiO
O
N
N OSiMe3 MeCH=N(O)OSiMe3
— 185
EtCH=N(O)OSiMe3
2 EtNO2 Me3SiCl C6H6 MeCH=N(O)OSiMe3 64 185
3 PrnNO2 Me3SiCl C6H6 EtCH=N(O)OSiMe3 79 185
4 NO2 Me3SiCl C6H6
O
N OSiMe3
— a 186
5
OH Me3SiCl C6H6 OSiMe3 O
—
NO2 N
OSiMe3 a 186
6 Me2CHNO2 Me3SiCl C6H6 Me2C = N(O)OSiMe3 0 186
7 Me2CHNO2 Me3SiCl MeCN
O
N
OSiMe3 +
N(OSiMe3) 2
72b OAc
187
8
AcO O
AcO
AcO
NO2 OAc Bu t Me2SiCl CH2Cl2
AcO
AcO
O
N
AcO
OSiMe2But O
30 b 183
9 R(CF3)CHNO2 c R’Me2SiCl Et2O R(CF3)C = N(O)OSiMe2R’ c 40-66 133
10 MeO2CCH2NO2 Me3SiOTf Et2O MeO2CCH = N(O)OSiMe3 85 188
R′ R
11 RCH2NO2 (R–H or alkyl) Me3SiCl C6H6 d O N
X 55-70b,c 186
12 RR’CHNO2 (R–H or alkyl; Me3SiCl MeCN
R’ – alkyl)
d or
MeCN/C6H6
O N
R
50-96 189
13
R
X
X
R′
OSiMe3 1
NO2 Me3SiCl C6H6 or
CH2Cl2
X
R1 R2 70-90e 190–196
14
R 2 R 3
R 1 ,R 2 ,R 3 − H, alkyl, aryl;
X − O, S, NCH2, CH=CH 2
R 2
X
R 1
NO 2
R 1 = H,Ph; R 2 = H,Me; X = O,CH 2
R 3
O N
Me3SiCl C6H6 R X 2 R1 a low conversion;
b by NMR;
c R= Me, Et; R’= Me, Bu t ,Pr i ;
d with addition XCH=CH2 or XCH=CHR 1 (X= CN, CO2Me, Ac; R 1 =H, alkyl);
e after treatment of adducts with TsOH, HCl, KF or Bu n 4NF.
O
21-98 e 190