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Tertiary stereogenic centres containing one fluorine atom are valuable for medicinal chemistry because they mimic common tertiary stereogenic centres containing one hydrogen atom, but they possess distinct charge distribution, lipophilicity, conformation and metabolic stability.sup.1-3. Although tertiary stereogenic centres containing one hydrogen atom are often set by enantioselective desymmetrization reactions at one of the two carbon-hydrogen (C-H) bonds of a methylene group, tertiary stereocentres containing fluorine have not yet been constructed by the analogous desymmetrization reaction at one of the two carbon-fluorine (C-F) bonds of a difluoromethylene group.sup.3. Fluorine atoms are similar in size to hydrogen atoms but have distinct electronic properties, causing C-F bonds to be exceptionally strong and geminal C-F bonds to strengthen one another.sup.4. Thus, exhaustive defluorination typically dominates over the selective replacement of a single C-F bond, hindering the development of the enantioselective substitution of one fluorine atom to form a stereogenic centre.sup.5,6. Here we report the catalytic, enantioselective activation of a single C-F bond in an allylic difluoromethylene group to provide a broad range of products containing a monofluorinated tertiary stereogenic centre. By combining a tailored chiral iridium phosphoramidite catalyst, which controls regioselectivity, chemoselectivity and enantioselectivity, with a fluorophilic activator, which assists the oxidative addition of the C-F bond, these reactions occur in high yield and selectivity. The design principles proposed in this work extend to palladium-catalysed benzylic substitution, demonstrating the generality of the approach. Enantioselective activation of a single C-F bond in a difluoromethylene group is achieved using a chiral transition metal catalyst and a fluorophilic activator., Author(s): Trevor W. Butcher [sup.1] , Jonathan L. Yang [sup.1] , Willi M. Amberg [sup.1] , Nicholas B. Watkins [sup.1] , Natalie D. Wilkinson [sup.1] , John F. Hartwig [sup.1] [...]

Eine allgemeine, intramolekulare Zykloisomerisierung nichtaktivierter Olefine mit Nukleophilen wird beschrieben. Die Reaktion erfolgt unter milden Bedingungen und toleriert Ether, Ester, geschützte Amine, Acetale, Pyrazole, Carbamate und Arene. Sie ist zugänglich für N‐, O‐ und C‐Nukleophile, wobei eine Reihe verschiedener Heterozyklen gebildet werden kann, darunter Pyrrolidine, Piperidine, Oxazolidinone und Lactone. Durch die Kombination eines Benzothiazinoquinoxalins als Organophotokatalysator und eines Cobaltsalen‐Katalysators sind keine stöchiometrischen Oxidations‐ oder Reduktionsmittel erforderlich. Wir zeigen den Nutzen des Protokolls für die Diversifizierung von Arzneimitteln sowie die Synthese mehrerer kleiner Naturstoffe. [ABSTRACT FROM AUTHOR]

Alkyl fluorides modulate the conformation, lipophilicity, metabolic stability, and pKa of compounds containing aliphatic motifs and, therefore, have been valuable for medicinal chemistry. Despite significant research in organofluorine chemistry, the synthesis of alkyl fluorides, especially chiral alkyl fluorides, remains a challenge. Most commonly, alkyl fluorides are prepared by the formation of C−F bonds (fluorination), and numerous strategies for nucleophilic, electrophilic, and radical fluorination have been reported in recent years. Although strategies to access alkyl fluorides by C−C bond formation (monofluoroalkylation) are inherently convergent and complexity‐generating, they have been studied less than methods based on fluorination. This Review provides an overview of recent developments in the synthesis of chiral (enantioenriched or racemic) secondary and tertiary alkyl fluorides by monofluoroalkylation catalyzed by transition‐metal complexes. We expect this contribution will illuminate the potential of monofluoroalkylations to simplify the synthesis of complex alkyl fluorides and suggest further research directions in this growing field. [ABSTRACT FROM AUTHOR]

We report a general, intramolecular cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and tolerates ethers, esters, protected amines, acetals, pyrazoles, carbamates, and arenes. It is amenable to N-, O-, as well as C-nucleophiles, yielding a number of different heterocycles including, but not limited to, pyrrolidines, piperidines, oxazolidinones, and lactones. Use of both a benzothiazinoquinoxaline as organophotocatalyst and a Co-salen catalyst obviates the need for stoichiometric oxidant or reductant. We showcase the utility of the protocol in late-stage drug diversification and synthesis of several small natural products., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

We report the synthesis and optoelectronic properties of 16 thiophene-based heterophenoquinones. These compounds were accessed in a convergent and modular approach, allowing for their efficient synthesis. Tuning of the optical band gap was achieved through π-extension by annulation of a benzene or tropone moiety to the thiophene, oxidation, change of the heteroatom or by attachment of a donor substituent to the thiophene core. The resulting compounds display intense colors covering the entire visible spectrum. We identified structure-property relationships and their impact on the HOMO and LUMO levels. Additionally, these materials change color upon reduction and according to in situ ultraviolet-visible-near infrared (UV-vis-NIR) and electron paramagnetic resonance (EPR) spectro-electrochemistry, they are promising electrochromes with cathodic color changes. Seven different electrochromic devices were constructed which all displayed a change in color upon reduction, demonstrating the potential of these new dyes in for example tintable glass., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)