BISMUTH(III) TRIFLATE - A WATER-STABLE EQUIVALENT OF TRIMETHYLSILYL TRIFLATE FOR THE CATALYSIS OF MUKAIYAMA ALDOL REACTIONS

Bismuth tris-trifluoromethanesulfonate (1) has been found to be an eff icient catalyst for the Mukaiyrtma aldol-type reactions. The catalytic activity of this catalyst is higher than the one previously reported for the rare earth triflates M(OTf)(3) (M = Sc, Ln). The mechanism may involve transmetallation between 1 and the silyl enol ether with form ation of trimethylsilyl triflate (2) which could be the true catalyst of the reaction. However, as 1 is water-stable, it can be recovered af ter reaction and therefore acts as a water-stable equivalent of 2.