Introduction
<P>Di-
n-butyltin oxide (DBTO), with the composition Bu
2SnO, is an amorphous, polymeric powder insoluble in nonreacting solvents. It has been
widely used for the selective manipulation of hydroxyl groups and polyols. The largest
application of DBTO in organic chemistry is in the generation and reactions of stannylenes
from polyhydroxy compounds. The stannylene acetals may be prepared by refluxing equimolar
mixtures of substrate and DBTO in benzene or toluene, with a Dean-Stark apparatus.
[
1]
Recently, Simas has reported that the stannylene intermediate formation does not require
removal of water.
[
2]
The synthesis of di-
n-butylstannylene is faster in methanol, but this solvent must be removed prior to
addition of the electrophile.
[
3]
Formation of these tin derivatives can be greatly accelerated by microwave irradiation.
[
4]
</P>
Preparation
<P>Di-
n-butyltin oxide is commercially available from most chemical suppliers. Diorganotin
oxides may be obtained by hydrolysis of diorganotin dihalides, diamides, dicarboxylates,
or dialkoxides. The hydrolysis is often reversible.
[
5]
Recently, Grossman developed a new procedure: powdered tin metal was reacted with
dry
n-butanol at 240 °C for 24 hours; DBTO was formed in 71% yield.
[
6]
</P>
