Mechanochemical trifluoromethoxylation of aryltrimethylammonium triflates, aryldiazonium tetrafluoroborates, and aryl pinacolboranes

Aryl trifluoromethyl ethers (ArOCF3) are important structural motifs in pharmaceuticals, agrochemicals, and functional materials. However, the methods reported for the efficient synthesis of these scaffolds are extremely underdeveloped and limited. Here, we report a highly efficient mechanochemical approach for the selective transformation of aryltrimethylammonium triflates, aryldiazonium tetrafluoroborates, and aryl pinacolboranes to aryl trifluoromethyl ethers via in situ-generated OCF3 source using triphosgene and Co(II) fluoride (CoF2). The proposed synthetic protocol also shows potential for the selective transformation of other groups such as arylsulfonium and diaryliodonium functionalities. The present trifluoromethoxylation strategy exhibited a broad functional group tolerance and found to be superior over other existing protocols in terms of substrate scope, yields, operational simplicity, and reaction times.