The reaction of 2,4,6-tris(trimethylsiloxy)-1,3,5-triazine with chlorocarbenium ions: a new access to 1-oxa-3-azabutatrienium and 2-azaallenium salts

Chlorocarbenium salts - of the Vilsmeier-Arnold type react with the silylated isocyanuric acid to give 1-oxa-3-azabutatrienium salts under mild conditions. From reactions of diarylchloromethenium salts - with and ketones or tertiary carboxamides high yields of 2-azaallenium salts were obtained. A few chloro substituted 2-azaallenium salts were prepared from and carbonyl compounds. The mechanisms of the new reactions are discussed.