New synthesis of 2-azoniaallene and triazenium salts from the reaction of nitrilium and cyanamidium salts with N-substituted imines

Abstract EN

N-Alkylnitrilium salts 1a-d were reacted with trisubstituted imines 5a-e to afford 2-azoniaallene salts 6a-h.

Competing with this reaction, trisubstituted imines 5a-d and N-alkylnitrilium salts 1c,d undergo [2++2+2] cycloaddition furnish triazenium salts 7a-d.

The addition of imines 5b,c to cyanamidium salt 1e afforded only 2-azoniaallene salts 6g,h.

The addition of guanidines 8 leads to 2-azoniaallene salts 9a,b through the degradation of the isolated addition product iminium salts 10a,b.

The synthesis and mechanisms of forming these compounds have been investigated.