Cyclopropanation of olefins by ethyl diazoacetate: Copper‐ and copper‐complex‐containing X‐zeolites as the catalysts

Abstract

AbstractCyclopropanation of olefins by ethyl diazoacetate has been carried out making use of the catalytic action of Cu‐loaded X‐type zeolites upon the decomposition of ethyl diazoacetate. The activity of the NaCuX zeolites is linearly dependent upon the Na‐exchange level. Compared to conventional copper catalysts, the zeolite catalysts give rise to relatively low amounts of polymeric side‐product which is assumed to be formed at the outer zeolite surface. The stereoselectivity obtained with the zeolite catalysts does not deviate significantly from that obtained using copper salts. Zeolite X, loaded with chiral copper complexes, gives rise to only minor asymmetric induction upon cyclopropanation of 1,1‐dichloro‐4‐methyl‐1,3‐pentadiene with ethyl diazoacetate.