| 摘要 |
Cyclic 6-membered to 8-membered 1,2-vinylenedioxy compounds of the general formula I <IMAGE> (I) where A is <IMAGE> R1 to R7 independently of one another are each hydrogen, C1-C8-alkyl, C2-C16-alkoxyalkyl, C2-C8-alkenyl, C2-C8-alkynyl, C5-C8-cycloalkyl, aryl, C7-C10-alkylphenyl, C7-C10-phenalkyl, C8-C10-phenalkenyl or a heterocyclic structure, or R2 and R3, R2 and R4, R3 and R4, R2 and R6, R3 and R6, R4 and R5 or R6 and R7together form a cycloaliphatic or heterocyclic ring, and R1 to R7 may furthermore carry substituents which are inert under the reaction conditions, and n is 0 or 1, are prepared by a process in which a cyclic 2-oxymethyl-1,3-dioxa compound or one of its derivatives of the general formula II <IMAGE> (II) where R1 to R7, A and n have the abovementioned meanings, and R8 is hydrogen or C1-C12-alkyl, is converted in the presence of an acidic catalyst at from 150 DEG to 450 DEG C. and under from 0.001 to 50 bar, some of the compounds obtained being novel.
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