| 摘要 |
A process is disclosed for chlorinating, brominating and/or iodinating an organic substrate containing both a single acidic hydrogen atom and at least one electron withdrawing group attached to the same carbon atom. The process replaces the single acidic hydrogen with chlorine, bromine and/or iodine and involves reacting the substrate in solution with a halogenating agent (e.g., a perhalomethane wherein the halogen substituents are I, Br and/or Cl, a trihaloacetic acid ester wherein the halogen substituents are Br and/or Cl, or a perfluoroalkyl halide wherein the halide is I, Br and/or Cl) in the presence of (i) a phase transfer catalyst of the formula R1R2R3R4LJ where L is selected from the group consisting of phosphorus and nitrogen, where J is an inorganic anion other than fluoride, and where R1, R2, R3 and R4 are independently chosen from the froup consisting of hydrocarbyl radicals containing from 1 to about 20 carbon atoms and (ii) a mild inorganic base which is insoluble in the reaction medium.
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