Process for the preparation of cyclic enol ethers

A process for the preparation of cyclic enol ethers of the formulae (I) and/or (II)

• which comprises cyclization of a starting compound of the formula (III)
• in which
• m is zero (0), one (1) or two (2),
• R1 is an organic radical with 1 to 20 carbon atoms,
• R2 is hydrogen or an organic radical having 1 to 20 carbon atoms,
• or the radicals R1and R2, together with the atoms connecting them, form a mono- or polycyclic, substituted or unsubstituted ring system with 3 to 20 carbon atoms which can also comprise heteroatoms selected from the group consisting of the elements Si, N, P, O, and S,
• R3 is hydrogen or an organic radical with 1 to 20 carbon atoms,
• R4 is hydrogen or an organic radical with 1 to 20 carbon atoms, and
• R5 is hydrogen or an organic radical with 1 to 20 carbon atoms,
• in the presence of a Brönstedt acid or Lewis acid, where the reaction is carried out as reactive distillation, where the formed cyclic enol ethers of the formulae (I) and/or (II) are separated off from the starting compound of the formula (III) by distillation from the reaction mixture.