27 research outputs found
From Olefination to Alkylation: In-Situ Halogenation of Julia–Kocienski Intermediates Leading to Formal Nucleophilic Iodo- and Bromodifluoromethylation of Carbonyl Compounds
Iodo- and bromodifluoromethylated compounds are important
synthetic
intermediates and halogen-bond acceptors. However, direct introduction
of −CF<sub>2</sub>I and −CF<sub>2</sub>Br groups through
nucleophilic addition is particularly challenging because of the high
tendency of decomposition of CF<sub>2</sub>Br<sup>–</sup> and
CF<sub>2</sub>I<sup>–</sup> to difluorocarbene. In this work,
we have developed a formal nucleophilic iodo- and bromodifluoromethylation
for carbonyl compounds. The key strategy of the method is the halogenation
of in situ-generated sulfinate intermediates from the Julia–Kocienski
reaction to change the reaction pathway from the traditional olefination
to alkylation. Interesting halogen−π interactions between
the halocarbon and aromatic donors were observed in the crystal structures
of the products. The method could also be extended to the introduction
of other fluorinated groups, such as −CFClBr, −CFClI,
−CFBr<sub>2</sub>, and −CFMeI, which opens up new avenues
for the synthesis of a wide range of useful fluorinated products
From Olefination to Alkylation: In-Situ Halogenation of Julia–Kocienski Intermediates Leading to Formal Nucleophilic Iodo- and Bromodifluoromethylation of Carbonyl Compounds
Iodo- and bromodifluoromethylated compounds are important
synthetic
intermediates and halogen-bond acceptors. However, direct introduction
of −CF<sub>2</sub>I and −CF<sub>2</sub>Br groups through
nucleophilic addition is particularly challenging because of the high
tendency of decomposition of CF<sub>2</sub>Br<sup>–</sup> and
CF<sub>2</sub>I<sup>–</sup> to difluorocarbene. In this work,
we have developed a formal nucleophilic iodo- and bromodifluoromethylation
for carbonyl compounds. The key strategy of the method is the halogenation
of in situ-generated sulfinate intermediates from the Julia–Kocienski
reaction to change the reaction pathway from the traditional olefination
to alkylation. Interesting halogen−π interactions between
the halocarbon and aromatic donors were observed in the crystal structures
of the products. The method could also be extended to the introduction
of other fluorinated groups, such as −CFClBr, −CFClI,
−CFBr<sub>2</sub>, and −CFMeI, which opens up new avenues
for the synthesis of a wide range of useful fluorinated products
From Olefination to Alkylation: In-Situ Halogenation of Julia–Kocienski Intermediates Leading to Formal Nucleophilic Iodo- and Bromodifluoromethylation of Carbonyl Compounds
Iodo- and bromodifluoromethylated compounds are important
synthetic
intermediates and halogen-bond acceptors. However, direct introduction
of −CF<sub>2</sub>I and −CF<sub>2</sub>Br groups through
nucleophilic addition is particularly challenging because of the high
tendency of decomposition of CF<sub>2</sub>Br<sup>–</sup> and
CF<sub>2</sub>I<sup>–</sup> to difluorocarbene. In this work,
we have developed a formal nucleophilic iodo- and bromodifluoromethylation
for carbonyl compounds. The key strategy of the method is the halogenation
of in situ-generated sulfinate intermediates from the Julia–Kocienski
reaction to change the reaction pathway from the traditional olefination
to alkylation. Interesting halogen−π interactions between
the halocarbon and aromatic donors were observed in the crystal structures
of the products. The method could also be extended to the introduction
of other fluorinated groups, such as −CFClBr, −CFClI,
−CFBr<sub>2</sub>, and −CFMeI, which opens up new avenues
for the synthesis of a wide range of useful fluorinated products
From Olefination to Alkylation: In-Situ Halogenation of Julia–Kocienski Intermediates Leading to Formal Nucleophilic Iodo- and Bromodifluoromethylation of Carbonyl Compounds
Iodo- and bromodifluoromethylated compounds are important
synthetic
intermediates and halogen-bond acceptors. However, direct introduction
of −CF<sub>2</sub>I and −CF<sub>2</sub>Br groups through
nucleophilic addition is particularly challenging because of the high
tendency of decomposition of CF<sub>2</sub>Br<sup>–</sup> and
CF<sub>2</sub>I<sup>–</sup> to difluorocarbene. In this work,
we have developed a formal nucleophilic iodo- and bromodifluoromethylation
for carbonyl compounds. The key strategy of the method is the halogenation
of in situ-generated sulfinate intermediates from the Julia–Kocienski
reaction to change the reaction pathway from the traditional olefination
to alkylation. Interesting halogen−π interactions between
the halocarbon and aromatic donors were observed in the crystal structures
of the products. The method could also be extended to the introduction
of other fluorinated groups, such as −CFClBr, −CFClI,
−CFBr<sub>2</sub>, and −CFMeI, which opens up new avenues
for the synthesis of a wide range of useful fluorinated products
AgF-Mediated Fluorinative Homocoupling of <i>gem</i>-Difluoroalkenes
A novel
silverÂ(I)-fluoride-mediated homocoupling reaction of β,β-difluoroÂstyrene
derivatives is described. The transformation is initiated via nucleophilic
addition of silverÂ(I) fluoride to β,β-difluoroÂstyrenes,
which is followed by dimerization of the corresponding benzylÂsilver
intermediates. The reaction shows good substrate scope, functional
group tolerance, and represents the first report on the reactivity
of (α-triÂfluoroÂmethyl)ÂbenzylÂsilver species
Copper-Mediated Fluoroalkylation of Aryl Iodides Enables Facile Access to Diverse Fluorinated Compounds: The Important Role of the (2-Pyridyl)sulfonyl Group
The (2-pyridyl)sulfonyl group was found to be a multifunctional group in the preparation of structurally diverse fluorinated products. It not only facilitates the copper-mediated (or catalyzed) cross-coupling reaction between α-fluoro sulfone 4a and aryl iodides, but also enables further transformations of the coupling products 2
AgF-Mediated Fluorinative Homocoupling of <i>gem</i>-Difluoroalkenes
A novel
silverÂ(I)-fluoride-mediated homocoupling reaction of β,β-difluoroÂstyrene
derivatives is described. The transformation is initiated via nucleophilic
addition of silverÂ(I) fluoride to β,β-difluoroÂstyrenes,
which is followed by dimerization of the corresponding benzylÂsilver
intermediates. The reaction shows good substrate scope, functional
group tolerance, and represents the first report on the reactivity
of (α-triÂfluoroÂmethyl)ÂbenzylÂsilver species
AgF-Mediated Fluorinative Homocoupling of <i>gem</i>-Difluoroalkenes
A novel
silverÂ(I)-fluoride-mediated homocoupling reaction of β,β-difluoroÂstyrene
derivatives is described. The transformation is initiated via nucleophilic
addition of silverÂ(I) fluoride to β,β-difluoroÂstyrenes,
which is followed by dimerization of the corresponding benzylÂsilver
intermediates. The reaction shows good substrate scope, functional
group tolerance, and represents the first report on the reactivity
of (α-triÂfluoroÂmethyl)ÂbenzylÂsilver species
Palladium-Catalyzed Monofluoromethylation of Arylboronic Esters with Fluoromethyl Iodide
The first palladium-catalyzed direct
monofluoromethylation of arylboronic esters to produce monofluoromethyl
arenes is reported. The reaction is typically carried out at room
temperature within 4 h and has a good functional group tolerance.
The monofluoromethylating agent, CH<sub>2</sub>FI, was readily prepared
via a halogen-exchange process
Iron-Catalyzed Difluoromethylation of Arylzincs with Difluoromethyl 2‑Pyridyl Sulfone
We report the first iron-catalyzed
difluoromethylation of arylzincs
with difluoromethyl 2-pyridyl sulfone via selective C–S bond
cleavage. This method employs the readily available, bench-stable
fluoroalkyl sulfone reagent and inexpensive iron catalyst, allowing
facile access to structurally diverse difluoromethylated arenes at
low temperatures. The experiment employing a radical clock indicates
the involvement of radical species in this iron-catalyzed difluoromethylation
process