51620-76-9Relevant academic research and scientific papers
C(sp3)-H Fluorination with a Copper(II)/(III) Redox Couple
Bower, Jamey K.,Cypcar, Andrew D.,Henriquez, Brenda,Stieber, S. Chantal E.,Zhang, Shiyu
supporting information, p. 8514 - 8521 (2020/05/28)
Despite the growing interest in the synthesis of fluorinated organic compounds, few reactions are able to incorporate fluoride ions directly into alkyl C-H bonds. Here, we report the C(sp3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogues, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized with single-crystal X-ray diffraction, X-ray absorption spectroscopy, UV-vis spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Quantum chemical calculations reveal significant halide radical character for all complexes, suggesting their ability to initiate and terminate a C(sp3)-H halogenation sequence by sequential hydrogen atom abstraction (HAA) and radical capture. The capability of HAA by the formally copper(III) halide complexes was explored with 9,10-dihydroanthracene, revealing that LCuF exhibits rates 2 orders of magnitude higher than LCuCl and LCuBr. In contrast, all three complexes efficiently capture carbon radicals to afford C(sp3)-halogen bonds. Mechanistic investigation of radical capture with a triphenylmethyl radical revealed that LCuF proceeds through a concerted mechanism, while LCuCl and LCuBr follow a stepwise electron transfer-halide transfer pathway. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.
Application of bidentate phosphite ester ligand in C-F bond construction reaction
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Paragraph 0026-0029; 0031, (2019/01/08)
The invention discloses an application of a bidentate phosphite ester ligand in C-F bond construction reaction. The bidentate phosphite ester ligand with different connecting structures can be appliedto the C-F bond construction reaction in the presence of an iron catalyst; under the co-catalytic effect of the ligand and iron salt, fluoridation of allyl alcohols occurs in an organic solvent; thebidentate phosphite ester ligand has a formula as shown in the specification; in the formula, Linker is one of 1,2-propylene glycol and glycol; a Linker is formed by removing H from hydroxy of corresponding diol and then linking with P; the bidentate phosphite ester ligand is used for catalyzing allyl fluoridation, the catalytic system is high in reaction activity and the substrate is wide in universality; in the catalytic system for constructing C-F bond and compounding different fluorine-containing organic compounds, the dosage of the reaction catalyst is low.
Palladium-catalyzed allylic C-H fluorination
Braun, Marie-Gabrielle,Doyle, Abigail G.
supporting information, p. 12990 - 12993 (2013/09/24)
The first catalytic allylic C-H fluorination reaction using a nucleophilic fluoride source is reported. Under the influence of a Pd/Cr cocatalyst system, simple olefin substrates undergo fluorination with Et3N·3HF in good yields with high branched:linear regioselectivity. The mild conditions and broad scope make this reaction a powerful alternative to established methods for the preparation of allylic fluorides from prefunctionalized substrates.
Regio- and stereoselective allylic trifluoromethylation and fluorination using CuCF3 and CuF reagents
Larsson, Johanna M.,Pathipati, Stalin R.,Szabo, Kalman J.
, p. 7330 - 7336 (2013/08/23)
Copper-mediated trifluoromethylation of allylic chlorides and trifluoroacetates was performed using a convenient Cu-CF3 reagent. The reaction is suitable for selective synthesis of allyl trifluoromethyl species. Mechanistic studies indicate that the reaction proceeds via a nucleophilic substitution mechanism involving allyl copper intermediates. The analogous Cu-F reagent was suitable for fluorination of allyl chlorides. Stereodefined cyclic substrates reacted regio- and stereoselectively.
Mechanistic studies on fluorocyclohexene conversion to fluorobenzene under Pd-catalyzed dehydrogenation
Tojo, Masahiro,Fukuoka, Shinsuke,Tsukube, Hiroshi
experimental part, p. 89 - 94 (2011/04/21)
The chemical reactivity and reaction mechanism of fluorobenzene formation by dehydrogenation of fluorocyclohexenes was investigated. 1-Fluorocyclohexene reacted with oxidants such as nitrobenzene and oxygen to give fluorobenzene in good yields under moderate conditions in the presence of a Pd catalyst. A detailed comparison of oxidative dehydrogenation with non-oxidative dehydrogenation proved that the oxidants effectively suppressed isomerization and disproportionation, and offered a selective synthesis of fluorobenzene.
Mechanistic studies on fluorobenzene synthesis from 1,1-difluorocyclohexane via pd-catalyzed dehydrofluorodehydrogenation
Tojo, Masahiro,Fukuoka, Shinsuke,Tsukube, Hiroshi
experimental part, p. 333 - 340 (2011/05/05)
The chemical reactivity and reaction mechanism of fluorobenzene synthesis via dehydrofluorodehydrogenation of 1,1-difluorocyclohexane was investigated. 1,1-Difluorocyclohexane reacted with molecular oxygen to give fluorobenzene in good yields in the presence of both Pd and metal fluoride catalysts. The reaction proceeded with dehydrofluorination of 1,1-difluorocyclohexane to yield 1-fluorocyclohexene as the sole intermediate species, followed by oxidative dehydrogenation. The present system offers a selective synthesis of fluorobenzene.
Palladium-catalyzed asymmetric synthesis of allylic fluorides
Katcher, Matthew H.,Doyle, Abigail G.
supporting information; experimental part, p. 17402 - 17404 (2011/02/23)
The enantioselective fluorination of readily available cyclic allylic chlorides with AgF has been accomplished using a Pd(0) catalyst and Trost bisphosphine ligand. The reactions proceed with unprecedented ease of operation for Pd-mediated nucleophilic fluorination, allowing access to highly enantioenriched cyclic allylic fluorides that bear diverse functional groups. Evidence that supports a mechanism in which C-F bond formation occurs by an SN2-type attack of fluoride on a Pd(II)-allyl intermediate is presented.
On the isolation of neat allylic fluorides
Lee, Eunsung,Yandulov, Dmitry V.
experimental part, p. 474 - 483 (2009/12/06)
Neat cinnamyl fluoride, geranyl fluoride, 5-carbomethoxy-3-fluorocyclohexene and parent 3-fluorocyclohexene undergo spontaneous decomposition on contact with borosilicate glass or catalytic quantities of moderately strong acids that consists in polycondensation with elimination of HF initiated by electrophilic abstraction of F-. Acid sensitivity of these allylic fluorides correlates with stability of respective allylic cations, exceeds that of parent benzyl fluoride, yet can be mitigated by the use of Teflon and PFA containers that permit their isolation and handling in the neat state.
A new synthesis of 2-fluoro-1-olefins
McCarthy, James R.,Matthews, Donald P.,Barney, Charlotte L.
, p. 973 - 976 (2007/10/02)
The first examples of the addition of PhSeF to olefins to yield β-fluoro phenylselenides (2) are reported. β-Fluoro phenylselenides (2) obtained from terminal olefins were converted to the title vinyl fluorides 3 on treatment with ozone, whereas, 2 obtain
Mechanistic aspects of the fluorination of cyclohexane and cyclohexene with acetyl hypofluorite in acetic acid
Visser, G. W. M.,Bakker, C. N. M.,Halteren, R. W. v.,Herscheld, J. D. M.,Brinkman, G. A.,Hoekstra, A.
, p. 214 - 219 (2007/10/02)
The reaction of acetyl hypofluorite in acetic acid with both cyclohexane and cyclohexene has been investigated.Analysis by GCMS and radio-HPLC, using (18)F as a tracer, revealed that apart from typical products expected from a radical reaction, several compounds originating from carbocationic intermediates were formed.On the basis of the observed products, a single-electrontransfer (SET) mechanism leading to an intermediate radical-cation is proposed.
