Switchable polymerisation catalysis enables block polymer sequence selectivity from monomer mixtures, resulting in the formation of multiblock polyesters. The aluminium salphen catalyst switches between two different polymerisation mechanisms and selectively enchains mixtures of commercially available monomers: lactide, phthalic anhydride, and propene oxide. Sequential monomer mixture additions yield multi‐block polyesters featuring 3, 7, 11, 15, 19, 23, and 27 blocks. The unparalleled catalytic selectivity can be used to access completely new multi‐block polyesters relevant for future applications.

A new organocatalyzed fluoride metathesis reaction between fluoroarenes and carbonyl derivatives is reported. The reaction exchanges fluoride (F − ) and alternate nucleophiles (OAc − , OCO 2 R − , SR − , Cl − , CN − , NCS − ). The approach provides a conceptually novel route to manipulate the fluorine content of organic molecules. When the fluorination and defluorination steps are combined into a single catalytic cycle, a byproduct free and 100% atom-efficient reaction can be achieved.

HF transfer reactions between organic substrates are potentially useful transformations. Such reactions require the development of catalytic systems that can promote both defluorination and fluorination steps in a single reaction sequence. Herein, we report a catalytic protocol in which an equivalent of HF is generated from a perfluoroarene | nucleophile pair and transferred directly to an alkyne. The reaction is catalyzed by [Au(IPr)N i Pr 2 ] (IPr = N , N ′-1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). HF transfer generates two useful products in the form of functionalized fluoroarenes and fluoroalkenes. Mechanistic studies (rate laws, KIEs, density functional theory (DFT) calculations, competition experiments) are consistent with the Au(I) catalyst facilitating a catalytic network involving both concerted S N Ar and hydrofluorination steps. The nature of the nucleophile impacts the turnover-limiting step. The cS N Ar step is turnover-limiting for phenol-based nucleophiles, while protodeuaration likely becomes turnover-limiting for aniline-based nucleophiles. The approach removes the need for direct handling of HF reagents in hydrofluorination and offers possibilities to manipulate the fluorine content of organic molecules through catalysis.

Schaltbare Polymerisationskatalyse ermöglicht die Synthese von Multiblock‐Polyestern mit hohen Selektivitäten bezüglich Blockpolymeren aus Mischungen von Monomeren. Der Al‐Salphen‐Katalysator “schaltet” zwischen zwei unterschiedlichen Polymerisationsmechanismen und polymerisiert hoch selektiv Mischungen der kommerziell verfügbarer Monomere Lactid, Phthalsäureanhydrid und Propylenoxid. Aufeinanderfolgende Zugaben von Monomermischungen erlauben die Synthese von Multiblock‐Polyestern mit 3, 7, 11, 15, 19 und 23 Blöcken. Diese einmalige Selektivität der Katalyse erlaubt die Verwendung von vollkommen neuen Multiblock‐Polyestern für zukünftige Anwendungen.