Cycloaddition of new N-unsubstituted azomethine ylides generated from N-[(trimethylsilyl) methyl]-thiocarbamates, synthetic equivalents of nonstabilized alkoxy- or alkylthionitrile ylides
O. Tsuge et al., Cycloaddition of new N-unsubstituted azomethine ylides generated from N-[(trimethylsilyl) methyl]-thiocarbamates, synthetic equivalents of nonstabilized alkoxy- or alkylthionitrile ylides, HETEROCYCLE, 55(2), 2001, pp. 249-254
The reaction of (trimethylsilyl)methyl isothiocyanate with alcohol in the p
resence of aluminum alkoxide provides a useful route for the preparation of
N- [(trimethylsilyl) methyl] thiocarbamates. The S-methylation of thiocarb
amates followed by desilylation generates nonstabilized azomethine ylides h
aving both methylthio and alkoxy groups at the ylide carbon. These azomethi
ne ylides react with electron-deficient carbon-carbon multiples bonds to gi
ve formal alkoxynitrile ylide- and/or methylthionitrile ylide-cycloadducts.
Thus, the azomethine ylides can be synthetic equivalents of nonstabilized
alkoxy- or methylthionitrile ylides that are otherwise relatively inaccessi
ble.