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

Si O Si
H
Si
O
Si
O N
+
ClC CCl
NOH NOH
N
O
415
H
Si
O
Si
APPLICATIONS OF NITRILE OXIDES 89
415
Et 3N
Scheme 1.52
Et3N
CH2Cl 2
H
Si
O
Si
H
O N
N
O
O O
N N
The yields of the Þrst and the second stages were 53% and 48%, respectively.
The yields of the para-analog of 414 were similar (55% and 35%, respectively).
A one-pot reaction with pyridine-2,6-biscarbohydroximinoyl dichloride gives a
pyridine analog of 414 as a minor product (8%). The main product 416 (25%
yield) arises from an intramolecular nitrile oxide dimerization. The macrocyclic
cycloadducts have been characterized spectroscopically and by X-ray crystallography
(452).
H
Si O Si
O H O
N N
N N
N
O
416
NO
414
H
Si
O
Si
H