Copper-catalyzed Chemoselective C-H Functionalization Of Quinoxalin-2(1H)-ones With Hexafluoroisopropanol

1,1,1,3,3,3-Hexafluoroisopropanol(HFIP,(CF₃)₂CHOH)is cheap and readily available.Due to the presence of two strong electron-withdrawing CF₃ group,HFIP possesses unique properties,such as high hydrogen-bond donating ability,high ionizing power,low nucleophilicity,and high oxidative stability.Taking advantage of these unique features,miscellaneous HFIP-promoted reactions have been developed.In comparison,the transformation of HFIP to fluorine-containing compounds has been less explored.In this thesis,copper-catalyzed fluoroalkylation of quinoxaline-2(1H)-one derivatives with HFIP as an easily available fluoroalkyl source in different oxidation systems have been developed.Firstly,under Cu Br-catalyzed and TBPB(tert-butyl peroxybenzoate)-oxidized conditions,a variety of hydroxyhexafluoroisobutylated quinoxalin-2(1H)-ones were formed.TBPB not only acts as an oxidant,but also as a source of methylene group.Then,the first hexafluoroisopropoxylation of quinoxalin-2(1H)-ones with HFIP is also demonstrated with Cu₂O as the catalyst and Ph I(OAc)₂ as the oxidant.The above reaction systems are easy to operate and reaction yields are excellent.These new transformations of HFIP furnish previously unknown and potentially useful fluorinated quinoxalin-2(1H)-one derivatives.