Cycloaddition of new n-unsubstituted azomethine ylides generated from n-[(trimethylsilyl)methyl]-thiocarbamates,synthetic equivalents of nonstabilized alkoxy-or alkylthionitrile ylides

摘要

The reaction of (trimethylsilyl)mthyl isothiocyanate with alcoholin the presence of aluminum alkoxide provides a useful route for the preparationof N-[(trimethylsilyl)methyl]thiocarboamates.The S-methylatoin of thiocarbamates followed by desilylation generates nonstabilized azomethine ylides haing both methylthio and alkoxy groups at the ylide carbon.These azomethine ylides react with electron-carbonmultiples bonds to give formal alkoxyitrile ylide-and/or methylthionitrile ylide-cycloadducts.Thus,the azometine ylides can be synthetic equivalents of nonstabilized alkoxy-or methylthionitrile ylides that are otherwise relatively inaccessible.