The first example of an amide-carbonyl stabilized oxiranyl anion: Generation from epoxysilane, its properties, and trapping with electrophiles

An epoxysilane having an amide group at the a-carbon was synthesized from phenylacetylene. An amide-carbonyl stabilized oxiranylammonium was generated from the epoxysilane in THF with tetrabutylammonium fluoride (TBAF). The generated oxiranyl anion was found to have enough nucleophilicity with aldehydes to give moderate to good yields of the adducts. In some reactions, the oxiranylammonium was found to be configurationally unstable to give the epimers.