Iodine(III)-Mediated Trifluoroacetylation of a C(sp²)–H or C(sp)–H Bond with Masked Trifluoroacyl Reagents

Abstract

A novel strategy for incorporating a trifluoroacetyl functionality into a range of structurally varied unsaturated bonds was developed by using PhI(OCOMe)₂ as an oxidant with a masked trifluoroacyl reagent as a trifluoroacetyl radical precursor. The oxidative decarboxylation of the masked trifluoroacyl precursor followed by a tandem radical process provides versatile access to 5-<i>exo</i>-<i>trig</i> cyclization of <i>N</i>-arylacrylamides, direct C(sp²)-H trifluoroacetylation of quinolines, isoquinoline, 2<i>H</i>-indazole, and quinoxalin-2(1<i>H</i>)-ones, and C(sp)-H trifluoroacetylation of alkynes. This protocol is characterized by mild reaction conditions, operational simplicity, and broad functional group compatibility.