Efficient generation of perfluoroalkyl radicals from sodium perfluoroalkanesulfinates and a hypervalent iodine(iii) reagent: mild, metal-free synthesis of perfluoroalkylated organic molecules

Abstract

This article describes an efficient method for the introduction of perfluoroalkyl groups into N-acrylamides, 2-isocyanides, olefins, and other heterocycles using perfluoroalkyl radicals that were generated from the reaction between sodium perfluoroalkanesulfinates and a hypervalent iodine(iii) reagent. This approach represents a simple, scalable perfluoroalkylation method under mild and metal-free conditions.

CF3SO2X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF3SO2Na

“…N -Arylacrylamides could also react with CF 3 SO 2 Na under metal-free conditions by replacing tert -butyl hydroperoxide or the persulfate by hypervalent iodine oxidants such as iodobenzene diacetate (PIDA, Scheme 28 ) [ 49 ], or iodobenzene bis(trifluoroacetate) (PIFA) [ 50 ]. Fu and co-workers proposed the reaction mechanism depicted in Scheme 28 .…”

“…Simultaneously, Lu and co-workers reported a transition-metal-free synthesis of the trifluoromethylphenanthridine 79a in 58% yield using the system CF 3 SO 2 Na/K 2 S 2 O 8 /K 2 CO 3 in H 2 O/CH 3 CN at 80 °C [ 90 ]. In addition, Maruoka and co-workers used the system CF 3 SO 2 Na/PIFA/AcONa in AcOEt at room temperature for 1.5 h to get 79a in 74% yield [ 50 ]. Mid 2017, Ao, Liu and co-workers exploited the reaction conditions developed previously for the photoredox trifluoromethylation of vinyl azides (see Scheme 8 ) in the synthesis of fluorinated phenanthridines 79 .…”

Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

“…In a similar manner, perfluoroalkylation of Nacrylamides, 2-isocyanides, olefins, and other heterocycles with sodium perfluoroalkanesulfinates and PhI (OCOCF 3 ) 2 was also explored (Scheme 52). [79] The transformation supplied a simple and convenient method for incorporation of perfluoroalkyl groups into a wide variety of organic molecules under mild and transition-metal-free conditions. It was assumed that perfluoroalkyl radicals were generated in situ from R fn SO 2 Na and PhI(OCOCF 3 ) 2 in the reactions, as addition of the radical scavenger TEMPO to a reaction mixture containing R fn SO 2 Na and PhI(OCOCF 3 ) 2 could successfully trap the perfluoroalkyl radical species.…”

“…It was assumed that perfluoroalkyl radicals were generated in situ from R fn SO 2 Na and PhI(OCOCF 3 ) 2 in the reactions, as addition of the radical scavenger TEMPO to a reaction mixture containing R fn SO 2 Na and PhI(OCOCF 3 ) 2 could successfully trap the perfluoroalkyl radical species. [79]…”

3‐Trifluoromethylated Coumarins and Carbostyrils by Radical Trifluoromethylation of ortho‐Functionalized Cinnamic Esters

“…First, the group of Dmowski succeeded in the synthesis of 3‐(trifluoromethyl)coumarins through the fluorination of 3‐carboxylated coumarins by using sulfur tetrafluoride as the fluorine source . Much more recently, several groups elaborated efficient methods for the direct trifluoromethylation of already existing coumarin scaffolds by using the Langlois or the Togni ( 1 ) reagent as the CF 3 source under transition‐metal‐mediated or metal‐free conditions . To date, only two examples involving the use of non‐coumarin scaffolds as starting materials have been reported (Scheme b) .…”