Cyclic acetals, processes for their production and conversion into herbicides.

摘要

Cyclic acetals of the formula I where the substituents have the following meaning: R<1> and R<2> are hydrogen, optionally substituted alkyl or phenyl; R<1> and R<2> together are further an optionally substituted C2-C6-alkylene chain; Y is oxygen or sulphur; A is a radical A<1> to A<6>; A<1> is hydroxyl; A<2> is a halogen atom, haloalkylsulphonyloxy, alkylsulphonyloxy or fluorosulphonyloxy; A<3> is cyano, nitro, formyl; A<4> is a phenyl ring or a 5- or 6-membered saturated or unsaturated heterocycle having up to four heteroatoms from the group consisting of nitrogen, sulphur and oxygen in the ring; naphthyl or a benzo-fused 5- or 6-membered heteroaromatic having 1 to 3 heteroatoms from the group consisting of nitrogen, sulphur and oxygen; A<5> is an alkenyl, cycloalkenyl, cycloalkadienyl or alkynyl group; A<6> is an alkyl or cycloalkyl group; where the radicals A<4>, A<5> or A<6> can be substituted; with the proviso that A is not a hydroxyl group if R<1> and R<2> are both hydrogen or if R<1> is hydrogen and R<2> is phenyl; processes for the preparation of the acetals I and their use for the production of plant protection agents.