Catalytic carbon-carbon bond-forming reactions of aminoalkane derivatives with imines

Catalytic C-C bond-forming reactions of aminoalkanes with imines were successfully performed using 9-fluorenylidene as a protecting and activating group of the nitrogen atom. The desired products were obtained in high yields with high diastereoselectivities using KO(t)Bu/18-crown-6 or potassium 2,6-dimethylphenoxide as a catalyst. A wide substrate scope, including simple aminoalkanes and a variety of imines, has been demonstrated. For the products obtained, selective deprotection was possible under acidic conditions to give the desired monoamine and diamine derivatives in high yields with quantitative recovery of 9-fluorenone. A preliminary study of a catalytic asymmetric variant showed promising enantioselectivity in the desired product.