Cyclocondensation of Amino-propargyl Silanes

Amino-propargyl silanes condense with carbonyl compounds to form imines and subsequently cyclize to form allenylidene tetrahydroquinolines. The cyclocondensations are catalyzed by a variety of Bronsted acids, among which phosphoric acids provide the highest yields. Subsequent intramolecular and intermolecular additions to the allene moiety provide complex polycyclic amines.