Catalytic Procedures for Multicomponent Synthesis of Imidazoles: Selectivity Control During the Competitive Formation of Tri- and Tetrasubstituted Imidazoles.

The catalytic potential of different fluoroboric acid-derived catalyst systems is investigated for the cyclocondensation reaction of α-diketones (I), aldehydes (II) and ammonium salt to form trisubstituted imidazoles (III) as well as the four component reaction using an additional amine (V) to afford tetrasubstituted derivatives (VI).