Operationally simple hydrotrifluoromethylation of alkenes with sodium triflinate enabled by Ir photoredox catalysis

Abstract

We report herein a single component Ir photoredox catalyst which is capable of catalyzing the hydrotrifluoromethylation of terminal alkenes and Michael acceptors with sodium triflinate (Langlois reagent) in methanol under irradiation at room temperature. Various synthetically useful functional groups, including ester, amide, ether, aldehyde, sulfone, ketone and aryl boronate, are well tolerated in this reaction.

Anti‐Markovnikov Hydroazidation of Alkenes by Visible‐Light Photoredox Catalysis

“…Subsequent single‐electron transfer (SET) between A and the reduced iridium(II) catalyst affords carbon anion intermediate B , from which product 2 a is formed by capturing a proton from HN 3 . Meanwhile, the photocatalyst is recovered and enters into the next catalytic cycle . Considering that the yield of 2 a decreased considerably when D 2 O was used in place of H 2 O (Scheme ), there must exist some other pathways to compete with the last protonation step.…”

“…To further evaluate the scope of this method, more functionalized alkenes were subjected to this protocol, and the results are presentedi nT able 3. The method is applicable to the preparation of 18, 19, 21, 22, 25-29 and 33,b ut failed in the cases of 20, 23,24,[30][31][32] and 34.S tyrene, allylbenzene, N-vinylbenzenesulfonamide, ethoxyethene,a nd limonene also could not be hydroazidated in this way,f or which either ac omplex mixture was obtained or substrates decomposed (see the Supporting Information).…”

“…As illustrated in Scheme 7w ith 1a takena sa ne xample, the initiation step is believed to be the oxidative generation of an azidyl radicalf rom TMSN 3 by the action of photoexcited [Ir(dF(CF 3 )ppy) 2 (dtbbpy)]PF 6 .G iven that TMSN 3 can react readily with H 2 Ot of orm HN 3 and TMSOH, it is also possible that the azidyl radicalderives from HN 3 by asingle electron oxidation [path (b)].T he azidyl radicalt hen adds onto 1a to give carbon radical A.S ubsequent single-electron transfer (SET) between A and the reduced iridium(II) catalysta ffords carbon anion intermediate B,f rom which product 2a is formed by capturing ap roton from HN 3 .M eanwhile, the photocatalyst is recovered ande nters into the next catalytic cycle. [23] Considering that the yield of 2a decreased considerably when D 2 Ow as used in place of H 2 O( Scheme 5), there must exist some other pathways to competew ith the last protonation step. The protonation needs to be fast to guarantee ac lean transformation and high yield;u sing D 2 Ow ould slow down protonation of B, thus resulting in decrease of the yield.…”

Markovnikov-Type Hydrotrifluoromethylchalcogenation of Unactivated Terminal Alkenes with [Me4N][XCF3] (X = S, Se) and TfOH

“…It serves as a central functionality for a wide variety of reactions. Hydrofluoroalkylation of alkenes constitutes a challenging task because of the difficulties of taming the elusive fluoroalkylation reagents with hydrogen sources [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. By using CF 3 SH, electrophilic “ + SCF 3 ” reagents, and trifluoromethanesulfonic anhydride (Tf 2 O), the respective hydrotrifluoromethylthiolation of alkenes has been successfully accomplished [ 66 , 67 , 68 , 69 , 70 ].…”

Iridium Tetra(4‐carboxyphenyl) Porphyrin, Calix[4]pyrrole and Tetraphenyl Porphyrin Complexes as Potential Hydrogenation Catalysts

“…At this juncture, to the best of our knowledge there are no reports on iridium‐based macromolecules (Scheme ). The development of such iridium complexes may broaden the scope as catalysts and may act as model molecules for biological, photophysical and chemical activities , . In other words, in recent years, great attention has been focused on the conversion of biomass into valuable chemicals, in which group VIII metal complexes play a vital role , , .…”