Process for the preparation of α-functionalized ketones

A process for the preparation of an α-functionalized ketone of the general formula I,

• wherein R1 and R2 are the same or different and are independently selected from H, linear or branched C1-C8-alkyl, C3-C8-cycloalkyl, linear or branched C2-C8-alkenyl, C5-C8-cycloalkenyl, linear or branched C2-C8-alkynyl, C6-C14-aryl or form C3-C12-cycloalkyl or C5-C12-cycloalkenyl together with the connecting C atom;
• R3, R4, R5, R6 and R7 are the same or different and are independently selected from H, linear or branched C1-C8-alkyl, linear or branched C2-C8-alkenyl, C1-C8-alkoxy, C2-C8-alkenyloxy, C3-C8-cycloalkyl, C6-C14-aryl, C3-C8-cycloalkoxy, C7-C15-arylalkoxy, C9-C15-alkenylarylalkoxy, N(R8)2 or SR8 with R8 being selected from linear or branched C1-C8-alkyl, linear or branched C2-C8-alkenyl, C6-C14-aryl, C1-C8-alkoxy, C2-C8-alkenyloxy, C3-C8-cycloalkyl, C3-C8-cycloalkoxy, C7-C15-arylalkoxy, C9-C15-alkenylarylalkoxy, or R8 form a C3-C9-alicyclic system together with the connecting N atom, optionally one or more carbon atoms are replaced with O, or two adjacent R form an aromatic system together with the benzene ring of formula I;
• Z is selected from OR9, NHR9 and NR10R11 with R9, R10 and R11 being independently selected from H, linear or branched C1-C8-alkyl, linear or branched C2-C8-alkenyl, C1-C8-alkoxy, C2-C8-alkenyloxy, C3-C8-cycloalkyl, C3-C8-cycloalkoxy, C6-C14-aryl, C7-C15-arylalkyl, C7-C15-arylalkoxy, C9-C15-alkenylarylalkoxy, C9-C15-alkenylarylalkyl;
• or R10 and R11 form a C3-C9-alicyclic system together with the connecting N or C atom, optionally one or more carbon atoms are replaced with O;
• the process comprising:
• contacting under phase-transfer conditions a ketone of the general formula II
• wherein R1, R2, R3, R4, R5, R6 and R7 are as defined above;
• with an at least partially halogenated C2-C8-alkane and/or C2-C8-alkene selected from hexachloroethane, tetrachloroethylene and mixtures thereof, and
• a base selected from the group comprising alkali metal hydroxide, earth alkali metal hydroxide, alkali metal C1-C8-alkoxide, earth alkali metal C1-C8-alkoxide and mixtures thereof, or a base selected from the group comprising alkali metal hydroxide, earth alkali metal hydroxide, alkali metal C1-C8-alkoxide, earth alkali metal C1-C8-alkoxide and mixtures thereof together with the protonated form of Z as defined above,
• wherein the base is added in form of an aqueous solution or the base is added in an organic solvent selected from the group consisting of methanol, ethanol, n-propanol, tert.-butanol, dichloromethane, tetrachloroethylene, ethyl acetate, acetone, N,N-dimethylformamide, dimethylsulfoxide, 1,2-dimethoxyethane, diethyleneqlycol dimethyl ether, triethyleneglycol dimethyl ether, and mixtures thereof.