Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
J Org Chem ; 89(10): 7084-7094, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38663869

RESUMEN

In this study, we have developed a smooth metal-free visible-light-induced bromo-perfluoroalkylation of unactivated olefins with the aid of 10-phenylphenothiazine (PTH) as an organic photoredox catalyst. The reaction is 100% atom-economic redox-neutral and proceeds with stoichiometric amounts of olefin and perfluoroalkyl bromide. To show the potential of these unexplored motifs, we carried out various postfunctionalizations taking advantage of the bromine atom, including gram-scale experiments.

2.
Angew Chem Int Ed Engl ; 63(34): e202407689, 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-38845586

RESUMEN

A photocatalyzed formal (3+2) cycloaddition has been developed to construct original polysubstituted α-SCF3 cyclopentanones in a regio- and diastereoselective manner. This building block approach leverages trifluoromethylthio alkynes and branched/linear aldehydes, as readily available reaction partners, in consecutive hydrogen atom transfers and C-C bond formations. Difluoromethylthio alkynes are also compatible substrates. Furthermore, the potential for telescoped reaction starting from alcohols instead of aldehydes was demonstrated, as well as process automatization and scale-up under continuous microflow conditions. This prompted density functional theory (DFT) calculations to support a radical-mediated cascade process.

3.
Chemistry ; 29(67): e202302914, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37698052

RESUMEN

In the vibrant field of SF5 chemistry, SF5 X reagents (X=F, Cl, Br) are at the heart of current investigations in radical pentafluorosulfanylation reactions. SF5 I is the missing link whose existence has not been reported despite its potential as SF5 donor. This study reports the formal addition of the hitherto unknown SF5 I reagent to alkynes by means of a combination of SF5 Cl/KI/18-crown-6 ether. The exclusive regio- and stereoselective synthesis of unprecedented (E)-1-iodo-2-(pentafluoro-λ6 -sulfanyl) alkenes was achieved. A consensus was reached through computational and mechanistic studies for the realistic formation of SF5 - anion but not SF5 I in solution and the rational involvement of SF5 ⋅ and iodine radicals in the iodo pentafluorosulfanylation reaction.

4.
Chem Rec ; 23(9): e202300096, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37096873

RESUMEN

From 2000, our two research groups independently and simultaneously designed and developed a novel family of electrophilic fluorinating reagents based on the use of Cinchona alkaloids. The chiral N-fluoro ammonium salts demonstrated the highest efficiency compared to prior art in enantioselective electrophilic fluorination for a wide range of substrates. In this account, we tell our respective stories, how the same idea germinated in our laboratories, the characterization of the chiral reagents, the use in stoichiometric quantity then the development of a catalytic version, the application to the synthesis of chiral fluorinated molecules of pharmaceutical interest, and finally the exploitation of our reagents by other teams and for other applications.

5.
Bioorg Med Chem Lett ; 91: 129363, 2023 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-37295616

RESUMEN

Fluorinated alcohols and phenols are potentially useful as bioisosteres of the carboxylic acid functional group. To enable a direct comparison of the properties of fluorinated carboxylic acid surrogates with those of other commonly used, non-fluorinated bioisosteres, we conducted a structure-property relationship (SPR) study based on matched molecular pair (MMP) analyses. A series of representative examples have been characterized by experimentally determining physicochemical properties, such as acidity (pKa), lipophilicity (logD7.4), and permeability (PAMPA). The results presented can help estimate the relative changes in physicochemical properties that may be attainable by replacing the carboxylic acid functional group with fluorine containing surrogate structures.


Asunto(s)
Alcoholes , Ácidos Carboxílicos , Ácidos Carboxílicos/química , Flúor/química
6.
J Org Chem ; 87(24): 16665-16675, 2022 12 16.
Artículo en Inglés | MEDLINE | ID: mdl-36417566

RESUMEN

Regioselective ring opening of cyclic sulfamidates was achieved by means of nucleophilic polyfluorinated alkoxides to access achiral and chiral ß- and γ-ORF amines and α-amino esters. Subsequent transformations provide free amines ready for incorporation into bioactive substances through amide bond formation or nucleophilic aromatic substitution.


Asunto(s)
Aminas , Éteres , Aminas/química , Ésteres
7.
J Org Chem ; 87(23): 15806-15819, 2022 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-36315641

RESUMEN

A protocol for the stereodivergent pentafluoroethylation of N-sulfinylimines using HFC-125 with KHMDS/triglyme has been developed. Both diastereomers of the pentafluoroethylated amines can be selectively synthesized based on the presence or absence of triglyme. This additive-controlled protocol allows the KHMDS/triglyme cryptate to be a straightforward and cheap alternative to previously reported base-controlled stereodivergent trifluoromethylation using potassium hexamethyldisilazide (KHMDS) versus P4-tBu.


Asunto(s)
Éteres Corona , Fluorocarburos , Polietilenglicoles
8.
J Org Chem ; 86(19): 13808-13816, 2021 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-34514785

RESUMEN

The radical 1,5-chloropentafluorosulfanylation of vinyl cyclopropanes (VCPs) initiated by Et3B/O2 affords allylic pentafluorosulfanyl/homoallylic chloride products through the ring-strain release of the cyclopropane. The VCP substitution pattern was investigated. The utility of this reaction was illustrated in post-transformation of the C═C bond by ozonolysis, giving access to valuable α-SF5 carbonyl compounds.


Asunto(s)
Cetonas
9.
Org Biomol Chem ; 18(3): 405-408, 2020 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-31915785

RESUMEN

We herein report a novel entry towards chiral α-SCF3-ß2,2-amino acids by carrying out the ammonium salt-catalyzed α-trifluoromethylthiolation of isoxazolidin-5-ones. This approach allowed for high enantioselectivities and high yields and the obtained heterocycles proved to be versatile platforms to access other targets of potential interest.

10.
Molecules ; 24(2)2019 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-30634428

RESUMEN

The first electrophilic diastereoselective direct introduction of the difluoromethylthio group is described. We used a chiral auxiliary-based approach to illustrate the versatility of our recently developed difluoromethanesulfonyl hypervalent iodonium ylide reagents for the difluoromethylthiolation of indanone-based ß-keto esters. Chiral SCF2H-featuring compounds were obtained in up to 93% ee value.


Asunto(s)
Ésteres/síntesis química , Indanos/química , Catálisis , Ésteres/química , Estructura Molecular , Estereoisomerismo
11.
Chemistry ; 24(30): 7749-7754, 2018 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-29566280

RESUMEN

A telescoping process involving the consecutive addition of four reagents (trifluorodiazoethane, phosphine, allenyl ester, and acetic acid) into a single reactor was developed for the novel functionalization of allenyl esters. First, new phosphazenes derived from trifluorodiazoethane and phosphines were generated and reacted with allenyl esters to give unexpected α-iminophosphoranes through the creation of C=P, C=N, and C-H bonds at the α-, ß-, and γ-carbon atoms, respectively, of the allenyl esters. The α-iminophosphoranes did not react with aldehydes in a classic Wittig reaction, but instead ß-enamino esters were obtained. The overall sequence of reactions offered a formal hydrohydrazonation of allenyl esters. The method was extended to other related diazo compounds and applied to the preparation of novel 5-pyrazolone derivatives. Not only is the telescoping process described herein an effective approach for truncating the multistep synthesis, but also each step has been dissected to understand and support the reaction mechanisms.

12.
Beilstein J Org Chem ; 13: 2764-2799, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-30018665

RESUMEN

Sodium trifluoromethanesulfinate, CF3SO2Na, and trifluoromethanesulfonyl chloride, CF3SO2Cl, are two popular reagents that are widely used for the direct trifluoromethylation of a large range of substrates. Further, these two reagents are employed for the direct trifluoromethylsulfenylation and trifluoromethylsulfinylation, the introduction of the SCF3 and the S(O)CF3 group, respectively. In addition to the aforementioned reactions, the versatility of these two reagents is presented in other reactions such as sulfonylation and chlorination. This first part is dedicated to sodium trifluoromethanesulfinate.

13.
Beilstein J Org Chem ; 13: 2800-2818, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-30018666

RESUMEN

The recent progresses of the application of trifluoromethanesulfonyl chloride, CF3SO2Cl, in the formation of C-CF3, C-SCF3, C-SOCF3, and C-Cl bonds are summarised in this second part of a two-part review published back-to-back on both sodium trifluoromethanesulfinate, CF3SO2Na, (Part 1) and trifluoromethanesulfonyl chloride, CF3SO2Cl (Part 2). There are many reactions in common between these two reagents but it should be noted that CF3SO2Cl reacts under reductive conditions while CF3SO2Na requires oxidative conditions. Electrophilic chlorination is obviously the exclusive preserve of CF3SO2Cl that has been exploited with emphasis in enantioselective chlorination.

14.
Chirality ; 28(2): 136-42, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26689286

RESUMEN

Enantiomerization of allylic trifluoromethyl sulfoxides occurs spontaneously at room temperature through the corresponding allylic trifluoromethanesulfenates via a [2,3]-sigmatropic rearrangement. Dynamic enantioselective high-performance liquid chromatography (HPLC) analysis revealed the stereodynamics of these sulfoxides ranging from chromatographic resolution to peak coalescence at temperatures between 5 and 53 °C. The rate constant of enantiomerization and activation parameters were determined and compared with Density Functional Theory (DFT) calculations.


Asunto(s)
Hidrocarburos Fluorados/química , Cromatografía Líquida de Alta Presión/métodos , Teoría Cuántica , Estereoisomerismo , Sulfóxidos/química
15.
Angew Chem Int Ed Engl ; 55(17): 5294-8, 2016 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-27001134

RESUMEN

CF3 -substituted 1,3-diols were stereoselectively prepared in excellent enantiopurity and high yield from CF3 -substituted diketones by using an ansa-ruthenium(II)-catalyzed asymmetric transfer hydrogenation in formic acid/triethylamine. The intermediate mono-reduced alcohol was also obtained in very high enantiopurity by applying milder reaction conditions. In particular, CF3 C(O)-substituted benzofused cyclic ketones underwent either a single or a double dynamic kinetic resolution during their reduction.

16.
J Org Chem ; 80(8): 4204-12, 2015 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-25791680

RESUMEN

The synthesis of trifluoromethylthiolated aliphatic acid derivatives by Pd-catalyzed C(sp(3))-H bond functionalization was developed. Using a bidentate directing group, the direct and selective introduction of a SCF3 moiety was possible on a range of amides with remarkable selectivity for C(sp(3))-centers with an electrophilic SCF3 source and pivalic acid as an additive. This work constitutes an example of the unactivated C(sp(3))-SCF3 bond formation by C-H activation offering a new access to relevant molecules.

17.
Chem Soc Rev ; 43(1): 135-47, 2014 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-24162874

RESUMEN

All domains of chemistry are increasingly impacted by organofluorine molecules, often favorably. In asymmetric synthesis of fluorinated compounds, significant achievements are the result of extensive research efforts toward appropriate experimental conditions rather than of the rationalization of fluorine effects. Most of the time, the influence of fluorine is inspected retrospectively. When elaborating a synthetic plan, the question should not be only when and how to introduce fluorine but also how to use the effects of fluorine for a desirable result. The subtle effects of fluorine atom(s) on the course of asymmetric reactions are outlined in this tutorial review. We present some selected examples of asymmetric reactions that involve fluorinated components either as reactants, catalysts, solvents or additives, and a comparative study of the stereochemical outcomes with reactions carried out in the presence of non-fluorinated analogues.

18.
J Org Chem ; 79(1): 413-8, 2014 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-24279496

RESUMEN

α- and ß-substituted N,N-diethylacrylamides undergo copper-mediated direct ß-trifluoromethylation. The amide moiety acts as a directing group for the regio- and the stereo-controlled introduction of the trifluoromethyl group. The reaction is carried out under acidic conditions in the presence of Umemoto's reagent. This method does not require prefunctionalized substrates and delivers excellent stereoselectivity.


Asunto(s)
Acrilamidas/química , Alquenos/química , Cobre/química , Hidrocarburos Fluorados/química , Catálisis , Metilación , Estructura Molecular , Estereoisomerismo
19.
Chimia (Aarau) ; 68(6): 378-81, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25198748

RESUMEN

The installation of fluorine atoms in reactants or catalysts has a dramatic impact on reactivity, regioselectivity and stereoselectivity. Several effects account for the modified stereochemical outcome of reactions with fluorinated versus non-fluorinated molecules. These effects are inherent to the specific properties of fluorine such as the size, the electronegativity, the chelation with metal cations, the hydrogen-bonding ability, the electrostatic and stereoelectronic interactions with neighbouring groups. The use of the effects of fluorine for a desirable goal in asymmetric synthesis is exemplified hereafter.

20.
Org Lett ; 26(17): 3657-3660, 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38657180

RESUMEN

CF3-substituted cyclopropyl carbinol derivatives undergo regioselective and diastereoselective nucleophilic halogenation at the quaternary carbon center to provide acyclic products as a single diastereomer. The selectivity of the substitution is rationalized by the formation of a nonclassical cyclopropylcarbinyl cation intermediate, reacting at the most-substituted carbon center. Tertiary alkyl chlorides, bromides, and fluorides adjacent to a stereogenic C-CF3-motif are diastereomerically pure and can be obtained in few catalytic steps from commercially available alkynes.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA