Spontaneous Cyclization of peri -Diiminonaphthalenes Leading to the Formation of Benzo[ de ]isoquinolines and Stable Benzo[ de ]isoquinoliniums.

The interaction of peri -dilithionaphthalenes with organic cyanides was studied. Instead of the expected peri -diimines, the reaction leads to the formation of three types of benzo[ de ]isoquinolines. Treatment of unsubstituted 1,8-dilithionaphthalene with aromatic nitriles results in the formation of 1-amino-1,3-diaryl-1 H -benzo[ de ]isoquinolines. In contrast, 4,5-dilithio-1,8-bis(dimethylamino)naphthalene gives an aromatic isoquinolonium cation via elimination of ammonia under the same condition. Upon treatment with tert -butylcyanide, both dilithionaphthalenes undergo a transformation to 1-amino-3,4-di- tert -butyl-4 H -benzo[ de ]isoquinolines. The observed reactivity was supported by quantum chemical calculations.