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

O
−
O O
+
NBoc− O
NBoc
N Bn
1. TBDMSOTf
2. HP(O)(OEt)2
THF, −20°C
O
O , BnO
+
N Bn
Scheme 2.202
1. TBDMSOTf
2. HP(O)(OEt)2
THF, −20°C
NBoc
O ,
Scheme 2.203
O
O
AcOH / H 2O
O
O
NBoc
AcOH / H2O
NBoc
NBoc
NITRONE REACTIONS 293
P(O)(OEt) 2
N(OH)Bn
Zn, Cu(OAc) 2
NHBn
,
,
P(O)(OEt) 2
O
S
O
P(O)(OEt) 2
N(OH)Bn
Zn, Cu(OAc)2
NHBn
P(O)(OEt) 2
O
O
NBoc
by the addition of an equimolar quantity of tert-butyldimethylsilyl trißate
(TBDMSOTf). This method makes it possible to use nitrones in the stereoselective
synthesis of various α-aminophosphonates and their N -hydroxy derivatives
(198, 692). They are of particular interest in biological researches (693, 694).
2.6.6.2. Nucleophilic Substitution in α-Haloalkylnitrones α-Monobromomethyl
derivatives of nitrones (298a) react with primary amines or hydrazine,
giving de-oxygenated products (213a). With α-bromoethyl derivatives (298b)
O