| abstract |
The invention relates to a method for producing enol ethers of formula (I), in which R<1> is an aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radical, which radicals can carry other substitutes that do not react with acetylenes or allenes; the R radicals are, independently of each other, hydrogen, or aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radicals, which can interconnect forming a ring; and m stands for 0 or 1. In this method, acetals or ketals of formula (II) are reacted with acetylenes or allenes of formula (III) or (IV), in which the R and R<1> radicals have the aforementioned meanings. The reaction takes place in the gas phase, at high temperature, in the presence of a heterogeneous catalyst containing zinc or cadmium together with silicon and oxygen. |