A four-component radical cascade trifluoromethylation reaction of alkenes enabled by an electron-donor–acceptor complex

Abstract

A four-component radical cascade trifluoromethylation of alkenes, enabled by an electron-donor–acceptor complex between Togni's reagent and Hantzsch ester, has been described.

Carboamination of Unactivated Alkenes through Three‐Component Radical Conjugate Addition

“…Such two‐component alkene couplings have been achieved following two different strategies: A) A widely reported approach uses radical cascades comprising an initial cyclization with subsequent intermolecular conjugate addition (Scheme b, left), and B) Baran realized a hydroalkylation of alkenes through radical additions, in which the nucleophilic C‐radicals are generated by addition of a Fe−H species to the alkene (Scheme b, right) . However, three‐component radical additions of unactivated alkenes to Michael acceptors where the C‐radicals are generated by intermolecular C−X bond formation leading to alkene 1,2‐difunctionalization products have not been reported …”

“…[11] However,t hree-component radical additions of unactivated alkenes to Michael acceptors where the C-radicals are generated by intermolecular C À Xb ond formation leading to alkene 1,2-difunctionalization products have not been reported. [12] As part of our program on N-radical chemistry, [13] we intended to achieve three-component carboamination of unactivated alkenes providing valuable d-amino ketone/ ester derivatives where the C-radical required for the Giese reaction is generated through amidyl radical addition to an unactivated alkene (Scheme 1c). [14] Carboamination of activated alkenes including styrenes and acrylates has gained attention recently, [15] but the herein disclosed strategy shoutable for unactivated alkenes has not been established to date.…”

Recent advances in transition-metal-free trifluoromethylation with Togni's reagents

“…In 2018, the Chu group reported an operationally simple approach for the chemoselective and regioselective synthesis of δ-CF 3 carbonyls 99 via a four-component radical cascade reaction (Scheme 20). 29 In the relevant study, investigations were conducted to acquire a deep insight into the reaction mechanism; for instance, the results of UV-vis absorption spectrometry and NMR titration experiments provided direct evidence of the generation of an EDA complex between the Hantzsch ester 96 and Togni's reagent 1. During the reaction, the CF 3 radical generated by the EDA complex is selectively added to the electron-rich alkene 97, so that the alkyl radical 103 is formed.…”

Visible-light Promoted Atom Transfer Radical Addition−Elimination (ATRE) Reaction for the Synthesis of Fluoroalkylated Alkenes Using DMA as Electron-donor

“…One of the major improvements has been made via photo-excited catalyst such as Ru/Ir complexes and organic dyes [21,33]. Very recently, non-covalent interaction initiated fluoroalkylation reaction has emerged as an attractive strategy [37][38][39][40][41][42][43][44][45][46][47]. Inspired by our previous studies in this field [48][49][50][51], we envision that if the solvent can serve as an electron donor compound, the reactions would be simpler.…”