Abstract:The direct and catalytic incorporation of fluorine containing molecular motifs into organic compounds resulting high-value added chemicals represents a rapidly evolving part of synthetic methodologies, thus this area is in the focus of pharmaceutical and agrochemical research. Herein we report a stereoselective procedure for direct fluorovinylation of aromatic and heteroaromatic scaffolds. This methodology development has been realized by palladium-catalyzed ortho CÀ H activation reaction of aniline derivative… Show more
“…By analogy, replacing the amides by amines (1,1-N,N-binucleophiles), gem-difluoro aziridine rings could be constructed. The above results have enriched the reaction mode of alkenyl iodonium salts 49 , 50 and provided a novel method for introducing gem-difluorovinyl group. Fig.…”
The synthesis of gem-difluoroethylene compounds remains a difficult task in organic synthesis. Here, the direct difluoroethylation reactions of N- and O-nucleophiles including amides and acids were realized with a hypervalent iodine reagent: gem-difluorovinyl iodonium salt (DFVI). The reactions were accomplished via a neighbouring group rearrangement. The gem-difluorovinyl iodonium salt was found to display diverse reactivity due to its unique electronic effect and was applied to the incorporation of difluoroethylene group, including difluorovinylation of carboxylic acids, difluorovinylation and 1,3-cyclic fluorovinylation of amides and 1,1-cyclic difluoroethylation of amines.
“…By analogy, replacing the amides by amines (1,1-N,N-binucleophiles), gem-difluoro aziridine rings could be constructed. The above results have enriched the reaction mode of alkenyl iodonium salts 49 , 50 and provided a novel method for introducing gem-difluorovinyl group. Fig.…”
The synthesis of gem-difluoroethylene compounds remains a difficult task in organic synthesis. Here, the direct difluoroethylation reactions of N- and O-nucleophiles including amides and acids were realized with a hypervalent iodine reagent: gem-difluorovinyl iodonium salt (DFVI). The reactions were accomplished via a neighbouring group rearrangement. The gem-difluorovinyl iodonium salt was found to display diverse reactivity due to its unique electronic effect and was applied to the incorporation of difluoroethylene group, including difluorovinylation of carboxylic acids, difluorovinylation and 1,3-cyclic fluorovinylation of amides and 1,1-cyclic difluoroethylation of amines.
“…49 Later, a Z-selective fluoroalkenylation has been achieved using iodonium salt as a coupling partner under the Pd(II)-catalysis (Scheme 14B). 50 Further, the Co(III)-catalyzed C8-olefination of QNO has been achieved with terminal alkyne as an alkenylating agent (Scheme 14C). 36 The uniqueness of the Co-catalyst has been shown to the alkenylation, competing with hydroarylation and OAT and the products are obtained with exclusive C8-selectivity.…”
Section: Scheme 13 Ru-catalyzed C8-alkenylation Of Thqsmentioning
confidence: 99%
“…49 In 2022, Tóth, Gonda, Novák, and coworkers reported a Z-selective fluoroalkenylation of THQs using an iodonium salt as the coupling partner under Pd(II) catalysis (Scheme 14B). 50 Also in 2022, Sharma, Sharma, and co-workers reported the Co(III)-catalyzed C8-alkenylation of QNOs with terminal alkynes as the alkenylating agent to give 8-(arylvinyl)-QNs (Scheme 14C). 36 The uniqueness of the Co catalyst in this alkenylation, competing with hydroarylation and OAT, has been shown and the QNs were obtained with exclusive C8-selectivity.…”
C8-Substituted quinoline (QN) and 1,2,3,4-tetrahydroquinoline (THQ) scaffolds are featured largely in a plethora of bio-active compounds and natural products. Appreciable efforts have thus been made towards the development of elegant techniques to functionalize the C8-H bond of QNs and THQs. Transition-metal-catalyzed chelation assisted C-H activation strategy has emerged as an effective synthetic tool among existing methods. This review focuses on the recent advances in the transition-metal-catalyzed directed carbon-carbon bond forming reactions for the C8-H functionalization of QNs and THQs (till February 2023). The discussion has been summarized categorically on the type of reactions.
“…[63] Our research group extended the Pd-catalyzed CÀ H activation reactions to the Z-selective fluoroalkenylation of aromatic compounds using various fluoroalkenyliodonium salts (Scheme 40). [64] Trifluoroacetic acid additive is also important in these reactions similarly to the trifluoroethylation reactions in order to reach high conversions in the catalytic process. Benzamide, aromatic ester or ketone directing groups (DG) are suitable for the functionalization, which are carried out in the presence of 7.5 mol% Pd(OAc) 2 , 2 equivalents of TFA, in DCM or DCE at ambient temperature for 5-24 hours.…”
Section: P E R S O N a L A C C O U N T T H E C H E M I C A L R E C O R Dmentioning
Synthesis and applications of fluoroalkyl and fluoroalkenyliodonium salts are summarized in this account article, focusing preferably to the reagents designed in our laboratory in the last decade. Among these reagents trifluoroethyl(aryl)iodonium salts have been used most frequently to build carbon‐carbon and carbon‐heteroatom bonds in simple nucleophilic substitutions and through transition metal catalyzed coupling reactions. Iodonium salts equipped with unsaturated fluorinated function showed diverse reactivity due to their electron deficient character, and these molecular motifs enable cycloadditions and nucleophilic additions to prepare fluorinated carbo‐ and heterocyclic molecules. Beyond the overview of existing transformations, with the presented collection, we aim to inspire future developments of iodonium reagents and their application in organic synthesis.
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