The cyclization of disilylated compounds catalyzed by trifluorornethanesulfonic acid is an easy way to obtain some heterocycles such as benzimidazole, triazole, furan and pyrrole.In-recent years, organosilicon reagents have found many applications in organic synthesis' : in the field of heterocyclic chemistry, the cyclization of silylated n compounds has been reported to give cyclic ethers' and carbamates , lactones , lactames , oxazolones6 and mesoionic oxazolones , imidazolidinediones , triazolones , oxadiazoles'O and aminotriazinones . 3 4 4 7 8 9 11 A general scheme appears from these cyclizations as well as from the heterocyclizations resulting of the 167 Copyright 0 1988 by Marcel Dekker, lnc.