The introduction of trifluoroalkyl groups into aromatic molecules is an important transformation in the field of organic and medicinal chemistry. However, the direct installation of fluoroalkyl groups onto aromatic molecules still represents a challenging and highly demanding synthetic task. Herein, a simple trifluoroethylation process that relies on the palladium-catalyzed C-H activation of aromatic compounds is described. With the utilization of a highly active trifluoroethyl(mesityl)iodonium salt, the developed catalytic method enables the first highly efficient and selective trifluoroethylation of aromatic compounds. The robust catalytic procedure provides the desired products in up to 95 % yield at 25 °C in 1.5 to 3 hours and tolerates a broad range of functional groups. The utilization of hypervalent reagents opens new synthetic possibilities for direct alkylations and fluoroalkylations in the field of transition-metal-catalyzed C-H activation.
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 derivatives featuring the regioselectivity via directing groups such as secondary of tertiary amides, ureas or ketones. The application of non-symmetrical aryl(fluoroalkenyl)-iodonium salts as fluoroalkenylating agents allowed mild reaction conditions in general for this transformation. The scope and limitations have been thoroughly investigated and the feasibility has been demonstrated by more than 50 examples.
The introduction of trifluoroalkyl groups into aromatic molecules is an important transformation in the field of organic and medicinal chemistry. However, the direct installation of fluoroalkyl groups onto aromatic molecules still represents a challenging and highly demanding synthetic task. Herein, a simple trifluoroethylation process that relies on the palladium‐catalyzed C−H activation of aromatic compounds is described. With the utilization of a highly active trifluoroethyl(mesityl)iodonium salt, the developed catalytic method enables the first highly efficient and selective trifluoroethylation of aromatic compounds. The robust catalytic procedure provides the desired products in up to 95 % yield at 25 °C in 1.5 to 3 hours and tolerates a broad range of functional groups. The utilization of hypervalent reagents opens new synthetic possibilities for direct alkylations and fluoroalkylations in the field of transition‐metal‐catalyzed C−H activation.
Information storage at the molecular level commonly entails
encoding
in the form of ordered sequences of different monomers and subsequent
fragmentation and tandem mass spectrometry analysis to read this information.
Recent approaches also include the use of mixtures of distinct molecules
noncovalently bonded to one another. Here, we present an alternate
isotope ratio encoding approach utilizing deuterium-labeled monomers
to produce hundreds of oligomers endowed with unique isotope distribution
patterns. Mass spectrometric recognition of these patterns then allowed
us to directly readout encoded information with high fidelity. Specifically,
we show that all 256 tetramers composed of four different monomers
of identical constitution can be distinguished by their mass fingerprint
using mono-, di-, tri-, and tetradeuterated building blocks. The method
is robust to experimental errors and does not require the most sophisticated
mass spectrometry instrumentation. Such isotope ratio-encoded oligomers
may serve as tags that carry information, but the method mainly opens
up the capability to write information, for example, about molecular
identity, directly into a pure compound via its isotopologue distribution
obviating the need for additional tagging and avoiding the use of
mixtures of different molecules.
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