Visible-light-promoted late-stage direct fluoroalkylation of nitroimidazoles

Direct Perfluoroalkylation of C−H Bonds in (Hetero)arenes

“…[113] Subsequently, the Liu group extended these processes to the direct difluoroacetamidation and the difluoromethylenephosphonylation of (hetero)arenes by using a very similar photocatalytic system and a large excess of the starting (hetero)aromatic substrate (Scheme 46, Equation (3)). [114] Additionally, the Bai, Chen, Wang and Zhang group also recently reported the perfluoroalkylation of nitroimidazoles in a similar manner [115] and the Li, Shi and Zhao group reported the para-selective difluoroalkylation of aniline derivatives. [116] The mechanism of theses reactions relies on the reduction of the difluoroalkyl bromide by the excited state of the iridium(III) photocatalyst to afford the key difluoroalkyl radical species that can then perform the alkylation of the (hetero)arene, as previously discussed.…”

“…Additionally, the use of fac-Ir(ppy) 3 was also recently reported by the Bai, Chen, Wang and Zhang group for the perfluoroalkylation of nitroimidazoles. [76] Most processes reported to date for the direct perfluoroalkylation of CÀ H bonds in (hetero)arenes with non-activated perfluoroalkyl halides have now been overviewed and discussed. Moving to activated ones, which enable the use of different methods for their activation and the introduction of other fluorinated alkyl chains, as highlighted in the next section of this review article.…”

Harnessing photocatalytic and electrochemical approaches for C–H bond trifluoromethylation and fluoroalkylation

“…Consequently, a visible-light-induced process involving difluoroalkyl bromide, perfluoroalkyl iodide 108 , and Togni's regent II 22 in the presence of an Ir( iii )-catalyst has been documented for the fluoroalkylation of nitroimidazoles (Scheme 44). 90 The observed reaction exhibited good functional group tolerance, indicating its potential applicability in diverse and complex chemical transformations. Intriguingly, several bioactive nitroimidazoles were effectively fluoroalkylated under these reaction conditions, yielding moderate to good product yields.…”

Review and Theoretical Analysis of Fluorinated Radicals in Direct CAr−H Functionalization of (Hetero)arenes

“…[134] Capitalizing on this concept, several other contributions have broadened the application of reagent 29 in the context of radical (hetero)aromatic functionalization. [135][136][137] Methyl fluorosulfonyl difluoroacetate (Chen's reagent, 30) was also employed as the carbomethoxy difluoromethylating reagent under visible light photoredox conditions (B). [138] Furthermore, the Liu and Li groups have also reported the difluoroacetamidation of (hetero)arenes using bromodifluoroacetamide 32 under photoredox conditions (B).…”

“…Within the realm of visible‐light photocatalysis, the adoption of ethyl bromodifluoroacetate ( 29 ) has been employed to accomplish heteroarene ethoxycarbonyl difluoromethylation through reductive SET process ( B ) [134] . Capitalizing on this concept, several other contributions have broadened the application of reagent 29 in the context of radical (hetero)aromatic functionalization [135–137] . Methyl fluorosulfonyl difluoroacetate (Chen's reagent, 30 ) was also employed as the carbomethoxy difluoromethylating reagent under visible light photoredox conditions ( B ) [138] .…”