N-ACYLIMINIUM SALTS FROM THE REACTION OF NITRILIUM SALTS WITH ALDEHYDES

The nitrilium hexachloroantimonates 2a, d, g, p react with aromatic aldehydes to give isolable N-acyl-iminium hexachloroantimonates 10a-m. The N-aroyliminium salts (10g-m) and acyliminium salts with an aliphatic N-acyl group (10a-f) are of remarkably different stability. Contrary to the N-aroyliminium salts, compounds 10a-f are unstable in solution, e. g. react immediately with acetonitrile. With excess of aldehyde 10n, o give insertion products of the probable structures 12a, b. For 10b, f X-ray structural analyses have been carried out. The N-acylcyanamidium hexachloroantimonate 2p reacts with aldehydes to give new classes of cyclic N-acyliminium salts 13a-f, and 14f, respectively.