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The accumulation of chiral ammonium‐oxocarbenium dications in superacid is evidenced by low‐temperature NMR spectroscopy, X‐ray diffraction analysis and confirmed by DFT calculations. Its potential for the diastereoselective remote hydrofunctionalization of non‐activated alkene is also explored. [ABSTRACT FROM AUTHOR]

Here we report a method to reorganize the core structure of aliphatic unsaturated nitrogen‐containing substrates exploiting polyprotonation in superacid solutions. The superelectrophilic activation of N‐isopropyl systems allows for the selective formal Csp3−H activation/cyclization or homologation / functionalization of nitrogen‐containing substrates. This study also reveals that this skeletal reorganization can be controlled through protonation interplay. The mechanism of this process involves an original sequence of C−N bond cleavage, isopropyl cation generation and subsequent C−N bond and C−C bond formation. This was demonstrated through in situ NMR analysis and labelling experiments, also confirmed by DFT calculations. [ABSTRACT FROM AUTHOR]

Understanding the influence of emerging fluorinated motifs is of a crucial importance in the context of the exponentially growing exploitation of fluorine in many fields. Herein, we report on the dramatic effect of a local partial charge inversion by replacing a CHCH3 group by a CFCF3. This strategy allows the diastereoselective reduction of 5-membered ring oxocarbenium ions to access highly substituted tetrahydrofurans. [ABSTRACT FROM AUTHOR]

Under superacid conditions, aromatic amines are directly and regioselectively 1,1‐difluoroethylated. Low temperature in situ NMR studies confirmed the presence of benzylic α‐fluoronium and α‐chloronium ions as key intermediates in the reaction. This method has a wide substrate scope and can be applied to the late‐stage functionalization of natural alkaloids and active pharmaceutical ingredients. [ABSTRACT FROM AUTHOR]

The accumulation of chiral ammonium-oxocarbenium dications in superacid is evidenced by low-temperature NMR spectroscopy, X-ray diffraction analysis and confirmed by DFT calculations. Its potential for the diastereoselective remote hydrofunctionalization of non-activated alkene is also explored., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Here we report a method to reorganize the core structure of aliphatic unsaturated nitrogen-containing substrates exploiting polyprotonation in superacid solutions. The superelectrophilic activation of N-isopropyl systems allows for the selective formal C sp3 -H activation/cyclization or homologation / functionalization of nitrogen-containing substrates. This study also reveals that this skeletal reorganization can be controlled through protonation interplay. The mechanism of this process involves an original sequence of C-N bond cleavage, isopropyl cation generation and subsequent C-N bond and C-C bond formation. This was demonstrated through in situ NMR analysis and labelling experiments, also confirmed by DFT calculations., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Since the pioneer reports of the groups of Akiyama and Terada on Brønsted acid organocatalysis, this field never stopped growing with the development of ingenious strategies for the activation of challenging poorly reactive substrates. The development of superacidic organocatalysts is an important way to selectively functionalize reluctant electrophiles and other approaches have also emerged such as the combination of Lewis and Brønsted acids as well as the consecutive organocatalysis and superacid activation. This Concept aims to highlight these different strategies and demonstrate their complementarity., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Understanding the influence of emerging fluorinated motifs is of a crucial importance in the context of the exponentially growing exploitation of fluorine in many fields. Herein, we report on the dramatic effect of a local partial charge inversion by replacing a CHCH 3 group by a CFCF 3 . This strategy allows the diastereoselective reduction of 5-membered ring oxocarbenium ions to access highly substituted tetrahydrofurans.

The field of medicinal chemistry is currently witnessing a deuterium rush owing to the remarkable properties of this element as bioisoster of hydrogen atom. Aromatic hydrogen isotope exchange (HIE) is one of the most studied strategies nowadays as it promises to access deuterium-modified drugs directly from their non-labeled parents. While most of the recent studies focus on metal-catalyzed C-H activation strategy, the use of superacidic conditions has been largely overlooked. This study shows that the use of TfOD as reaction medium allows the late-stage polydeuteration of a broad library of pharmaceuticals bearing a wide array of functional groups, complementing existing procedures., (© 2022 Wiley-VCH GmbH.)

Enantioenriched complex fused-tricyclic azepanes or bridged-polycyclic azocanes were constructed via a two-step sequence involving an enantioselective organocascade followed by superacid activation of the domino adduct. The activated oxa-bridged azepane acts as a key hidden heptacyclic chiral N-acyl iminium ion triggering a chemo- and diastereoselective intramolecular mono- or di-arylation., (© 2022 Wiley-VCH GmbH.)

Under superacid conditions, aromatic amines are directly and regioselectively 1,1-difluoroethylated. Low temperature in situ NMR studies confirmed the presence of benzylic α-fluoronium and α-chloronium ions as key intermediates in the reaction. This method has a wide substrate scope and can be applied to the late-stage functionalization of natural alkaloids and active pharmaceutical ingredients., (© 2021 Wiley-VCH GmbH.)