Selective aromatic carbon–oxygen bond cleavage of trifluoromethoxyarenes: a trifluoromethoxy group as a convertible directing group

Aryl Silyl Ethers Enable Preferential Ar-O bond Cleavage in Reductive Generation of Aryllithium Species

Two-electron transfer to haloarenes constitutes one of the most reliable synthetic methodologies for the generation of aryllithiums. In addition to the conventional halides, readily available aryl ethers can function as potent substrates. However, it is known that the reductive cleavage of alkoxides is plagued by insufficient selectivity concerning the cleaving bond adjacent to the ether oxygen, resulting in decreased reliability of these alkoxyarene substrates. In the present study, we discovered that naphthalenes bearing readily installable tert-butyldimethylsilyl ethers undergo two-electron reduction with lithium metal, resulting in lithiation at the position of the original siloxy group. DFT calculations elucidated the rationale for the change in selectivity upon incorporation of the siloxy group. Our results underscore the practical utility of a siloxy group as a leaving group for reductive transformations involving electron transfer.

Sequential Xanthalation and O-Trifluoromethylation of Phenols: A Procedure for the Synthesis of Aryl Trifluoromethyl Ethers

Molecules containing trifluoromethoxyaryl groups are of interest in pharmaceutical, agrochemical, and materials science research, due to their unique physical and electronic properties. Many of the known methods to synthesize aryl trifluoromethyl ethers require harsh reagents and highly controlled reaction conditions and rarely occur when heteroaromatic units are present. The two-step O-trifluoromethylation of phenols via aryl xanthates is one such method that suffers from these drawbacks. Herein, we report a method for the synthesis of aryl trifluoromethyl ethers from phenols by the facile conversion of the phenol to the corresponding aryl and heteroaryl xanthates with newly synthesized imidazolium methylthiocarbonothioyl salts and conversion of these xanthates to the trifluoromethyl ethers under mild reaction conditions.

Aryl-BIAN-ligated silver(i) trifluoromethoxide complex

The complex (Aryl-BIAN)AgOCF₃ has been synthesised and structurally characterised. The reactivity towards trifluoromethoxylation of benzyl bromides has also been examined.