Cyclopropanation reactions catalysed by copper(II)-exchanged clays and zeolites. Influence of the catalyst on the selectivity

Abstract

The reaction of ethyl diazoacetate with styrene is catalysed by Cu^II-exchanged clays and zeolites; the trans/cis selectivity strongly depends on the nature of the catalyst and when using Cu^II-K10 montmorillonite the normal selectivity in solution is reversed and the cis-cyclopropane is the major product. The tendency of this catalyst to increase the amount of the product less favoured in solution is confirmed in other reactions.