A Radical Access to CF₃- and SF₅-Containing Dihydrobenzofurans and Indolines

^‡ These authors contributed equally to this work.

Abstract

The synthesis of 3-(2,2,2-trifluoroethyl)-2,3-dihydrobenzofurans, 3-(2,2,2-trifluoroethyl)indolines, 3-[(pentafluorosulfanyl)methyl]-2,3-dihydrobenzofurans, and 3-[(pentafluorosulfanyl)methyl]indolines using an intramolecular reductive radical cyclization from readily available acyclic precursors is reported. The CF₃- and SF₅-containing heterocycles are obtained in moderate to excellent yields. Notably, this transformation represents the first example of an aryl radical addition to a SF₅-containing alkene. Finally, the possibility of oxidation of some of the products generated to benzofurans and indoles is shown.

Key words

heterocycles - fluorine - radical reaction - pentafluorosulfanyl - trifluoromethyl - dihydrobenzofurans - indolines

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