2-Chloro-2,2-difluoroacetophenone:A Non-ODS-Based Difluorocarbene Precursor and Its Use in the Difluoromethylation of Phenol Derivatives

摘要

A novel and non-ODS-based (ODS =ozone-depleting substance)preparation of 2-chloro-2,2-difluoroacetophenone (1)was achieved in high yield by using 2,2,2-trifluoroac-etophenone as the starting material.Compound 1 was found to act as a good difluorocarbene reagent,which readily reacts with a variety of structurally diverse phenol derivatives 4 in the presence of potassium hydroxide or potassium carbonate to produce aryl difluoromethyl ethers 5 in good yields.This new and easy-to-handle synthetic methodology offers an environmentally friendly alternative to other Freon- or Halon-based difluoromethylating approaches.