Patent ID: 6903221

Claim:
A process for preparing β-ketoenol esters of the formula Ia or Ib in which R a , R b independently of one another are C 1 -C 6 -alkyl or C 3 -C 8 -cycloalkyl, or R a and R b together are C 2 -C 4 -alkanediyl or C 5 -C 7 -cycloalkanediyl, where the three groups mentioned above may be substituted or unsubstituted and may have a fused 3-, 4-, 5- or 6-membered saturated carbocycle, a spiro-linked 3-, 4-, 5- or 6- or 7-membered saturated carbocycle, a spiro-linked 3-, 4-, 5-, 6- or 7-membered saturated heterocycle having 1 or 2 chalkogen atoms, selected from the group consisting of oxygen and sulfur and/or a carbonyl or thiocarbonyl group; Ar is phenyl or pyridyl, which may in each case have 1, 2, 3 or 4 substituents, it also being possible for two substituents attached to adjacent carbon atoms to form, together with these atoms, a 5- or 6-membered saturated or unsaturated carbocycle or a 5- or 6-membered saturated or unsaturated heterocycle which has 1, 2 or 3 hetero atoms selected from the group consisting of O, N and S and which for its part may be substituted or unsubstituted; which comprises reacting an aryl halide of the formula II Ar-Hal (II) in which Hal is bromine with a 1,3-diketone of the formula III or its tautomer III′ or III″ in a carbon monoxide atmosphere in the presence of a base and a catalyst which comprises at least one transition metal of group VIII of the Periodic Table of the Elements.