Process for the epoxidation of CIS double bonds

A method for the synthesis of a macrocyclic monoepoxide having at least one double bond, comprising:

• reacting a macrocyclic aliphatic hydrocarbon with 8 to 20 ring carbon atoms and 2 to 5 isolated double bonds, said aliphatic hydrocarbon having at least one cis double bond and at least one trans double bond, with hydrogen peroxide in two liquid phases in the presence of a catalyst system, wherein said catalyst system is a homogeneous catalyst system comprising an oxidation catalyst and a phase transfer catalyst, wherein said oxidation catalyst comprises a polyoxometallate of tungsten or molybdenum and at least one element selected from the group consisting of germanium, tin, lead, arsenic, antimony, bismuth, selenium, tellurium and polonium, and wherein said polyoxmetallate has a sandwich structure.