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1. Pd-Catalyzed Suzuki-Miyaura Cross-Coupling of Pentafluorophenyl Esters

   https://doi.org/10.3390/molecules23123134  

   Buchspies, Jonathan; J. Pyle, Daniel; He, Huixin; Szostak, Michal (December 2018, Molecules)

   Although the palladium-catalyzed Suzuki-Miyaura cross-coupling of aryl esters has received significant attention, there is a lack of methods that utilize cheap and readily accessible Pd-phosphane catalysts, and can be routinely carried out with high cross-coupling selectivity. Herein, we report the first general method for the cross-coupling of pentafluorophenyl esters (pentafluorophenyl = pfp) by selective C–O acyl cleavage. The reaction proceeds efficiently using Pd(0)/phosphane catalyst systems. The unique characteristics of pentafluorophenyl esters are reflected in the fully selective cross-coupling vs. phenolic esters. Of broad synthetic interest, this report establishes pentafluorophenyl esters as new, highly reactive, bench-stable, economical, ester-based, electrophilic acylative reagents via acyl-metal intermediates. Mechanistic studies strongly support a unified reactivity scale of acyl electrophiles by C(O)–X (X = N, O) activation. The reactivity of pfp esters can be correlated with barriers to isomerization around the C(acyl)–O bond. 

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2. Exploring high molecular weight vinyl ester polymers made by PET-RAFT

   https://doi.org/10.1039/D4PY00065J  

   Weerasinghe, M. A.; De Alwis Watuthanthrige, Nethmi; Konkolewicz, Dominik (February 2024, Polymer Chemistry)

   Polyvinyl esters are used in many applications, however, high molecular weight polyvinyl esters have many challenges, with strategies for the synthesis of these polymers being the focus of this work. 

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3. Autohydrolysis of Diglycine‐Activated Succinic Esters Boosts Cellular Uptake

   https://doi.org/10.1002/anie.202308022  

   Guo, Jiaqi; Tan, Weiyi; He, Hongjian; Xu, Bing (September 2023, Angewandte Chemie International Edition)

   Abstract Rapid cellular uptake of synthetic molecules remains a challenge, and the motif frequently employed to generate prodrugs, succinic ester, unfortunately lowers the efficacy of the desired drugs due to their slow ester hydrolysis and low cell entry. Here we show that succinic ester‐containing diglycine drastically boosts the cellular uptake of supramolecular assemblies or prodrugs. Specifically, autohydrolysis of the diglycine‐activated succinic esters turns the nanofibers of the conjugates of succinic ester and self‐assembling motif into nanoparticles for fast cellular uptake. The autohydrolysis of diglycine‐activated succinic esters and drug conjugates also restores the efficacy of the drugs. 2D nuclear magnetic resonance (NMR) suggests that a “U‐turn” of diglycine favors intramolecular hydrolysis of diglycine‐activated succinic esters to promote autohydrolysis. As an example of rapid autohydrolysis of diglycine‐activated succinic esters for instant cellular uptake, this work illustrates a nonenzymatic bond cleavage approach to develop effective therapeutics for intracellular targeting. 

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4. Direct electrochemical synthesis of pentafluorophenyl esters via oxyl-radical-promoted nucleophilic aromatic substitution

   https://doi.org/10.1039/D5OB00798D  

   Hilvano, Edward_G V; Liang, Min-Chieh; Piane, Jacob J; Nacsa, Eric D (July 2025, Organic & Biomolecular Chemistry)

   An electrochemical coupling between carboxylic acids and penta uorophenol (PFP–OH) to access synthetically versatile penta uorophenyl (PFP) esters has been developed. Novel reactivity of PFP–OH was turned on by modulating its oxidation state, leveraging both its native O-nucleophilicity and its latent, oxidation-induced C-electrophilicity to promote a unique cascade of nucleophilic aromatic and acyl substitutions. Its esteri cation with acids was thus achieved for the rst time without exogenous dehydrating agents. The acidity of PFP–OH and the oxidizability of its conjugate base enabled its mild and selective activation via deprotonation–oxidation, readily affording PFP esters that are useful in many applications (peptide synthesis, chemical biology, etc.) and that contain redox-sensitive functional groups. Finally, we verified in a unified forum that an amino-acid-derived PFP ester can be converted into a range of acyl-substitution products while retaining key stereochemical information, and we demonstrated that PFP esters have excellent stability to hydrolysis, comparing favorably even to N-hydroxysuccinimidyl (NHS) esters. 

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5. Reaction of Carboxylic Acids and Dehydroalanine Allyl Esters via One‐Pot Sequential Decarboxylative Couplings

   https://doi.org/10.1002/cctc.202500696  

   Londhe, Shrikant_S; Waller, Colin_W; Tunge, Jon_A (June 2025, ChemCatChem)

   Abstract A protocol for the iterative decarboxylative cross‐coupling of carboxylic acids with dehydroalanine (Dha) allyl esters is described. A procedure for decarboxylative Giese addition to dehydroalanine allyl esters that avoids 5‐exo‐trig radical cyclization onto the allyl moiety was developed. This results in complex, substituted alanine allyl esters that are poised for a second decarboxylative coupling. Thus, following the photocatalytic decarboxylative alkylation of Dha, the resulting amino acid allyl esters were subjected to decarboxylative allylation under metallaphotoredox/palladium catalysis. The Giese addition and decarboxylative allylation can be performed in one pot simply by triggering the decarboxylative allylation by addition of a palladium catalyst. These one‐pot decarboxylative couplings leverage temporally controlled carboxylate formation to allow controlled, sequential photoredox activation of the carboxylates. The ability to perform sequential, one‐pot photoredox C─C bond formations obviates the need for isolation of intermediates. The final products of these coupling reactions are densely functionalized homoallylic amines and/or unsymmetric, differentiated 1,3‐diamines, both known for their high synthetic value. 

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