Method for preparing cis-alkoxy-substituted spirocyclic 1-H-pyrrolidine-2,4-dione derivatives

A method for preparing a compound of formula (I)

• in which
• X is C1-C6-alkyl, halogen, C1-C6-alkoxy, C1-C6-haloalkyl or C1-C6-haloalkoxy,
• Y is hydrogen, C1-C6-alkyl, C1-C6-alkoxy, halogen, C1-C6-haloalkyl or C1-C6-haloalkoxy, wherein only one of the radicals X or Y may be C1-C6-haloalkyl or C1-C6-haloalkoxy,
• A is C1-C6-alkyl,
• G is the group
• in which
• R′ is C1-C20-alkyl, C2-C20-alkenyl, C1-C8-alkoxy-C2-C8-alkyl or poly-C1-C8-alkoxy-C2-C8-alkyl, in each case optionally substituted by halogen,
• is C3-C8-cycloalkyl optionally substituted by halogen, C1-C6-alkyl or C1-C6-alkoxy or
• is phenyl or benzyl in each case optionally substituted by halogen, cyano, nitro, C1-C6-alkyl, C1-C6-alkoxy, C1-C6-haloalkyl or C1-C6-haloalkoxy,
• wherein firstly a compound of formula (II)
• in which X, Y and A are as defined above and
• R″ is C1-C6-alkyl,
• are cyclized in the presence of a base and in the presence of one or more solvents to give compound of formula (III)
• in which X, Y and A are as defined above and
• M is an alkali metal ion, an ion equivalent of an alkaline earth metal, an ion equivalent of aluminium or an ion equivalent of a transition metal, or further
• is an ammonium ion, in which optionally one, two, three or all four hydrogen atoms can be replaced by identical or different radicals from the groups C1-C5-alkyl, C1-C5-isoalkyl or C3-C7-cycloalkyl, which can in each case be substituted one or more times with fluorine, chlorine, bromine, cyano, hydroxy or be interrupted by one or more oxygen or sulphur atoms, or further
• is a cyclic secondary or tertiary aliphatic or heteroaliphatic ammonium ion, or further
• is a heterocyclic ammonium cation, or further
• is a sulphonium ion, or further
• is a magnesium halogen cation,
• m is the number 1, 2 or 3,
• n is the number 1, 2 or 3
• and are reacted with a compound of formula (IV)
• in which
• R′ is C1-C6-alkyl,
• q is the number 0 or 1,
• and Hal represents halogen,
• optionally in the presence of one or more solvents and optionally in the presence of an acid binder and optionally in the presence of a phase transfer catalyst.