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1. Decarbonylative thioetherification by nickel catalysis using air- and moisture-stable nickel precatalysts

   Liu, Chengwei; Szostak, Michal (February 2018, Chemical communications)

   A general, highly selective method for decarbonylative thioetherification of aryl thioesters by C–S cleavage is reported. These reactions are promoted by a commercially-available, userfriendly, inexpensive, air- and moisture-stable nickel precatalyst. The process occurs with broad functional group tolerance, including free anilines, cyanides, ketones, halides and aryl esters, to efficiently generate thioethers using ubiquitous carboxylic acids as ultimate cross-coupling precursors (cf. conventional aryl halides or pseudohalides). Selectivity studies and site-selective orthogonal cross-coupling/thioetherification are described. This thioester activation/coupling has been highlighted in the expedient synthesis of biorelevant drug analogues. In light of the synthetic utility of thioethers and Ni(II) precatalysts, we anticipate that this user-friendly method will be of broad interest. 

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2. Cobalt−NHC Catalyzed C(sp ² )−C(sp ³ ) and C(sp ² )−C(sp ² ) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents

   https://doi.org/10.1002/cctc.202001347  

   Piontek, Aleksandra; Ochędzan‐Siodłak, Wioletta; Bisz, Elwira; Szostak, Michal (November 2020, ChemCatChem)

   Abstract The first cobalt‐catalyzed cross‐coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF₃and NHCs (NHC=N‐heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C−O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp²)−C(sp³) cross‐coupling of C−O electrophiles, circumventing isomerization and β‐hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C−O cross‐coupling sets the stage for a sequential cross‐coupling by exploiting the orthogonal selectivity of the catalytic system. 

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3. General Base‐Free Suzuki‐Miyaura Cross‐Coupling Reaction via Electrophilic Substitution Transmetalation

   https://doi.org/10.1002/anie.202512496  

   Zhang, Meng; Shan, Jing‐Ran; Xie, Yuke; Wei, Lanen; Xiong, Haigen; Xie, Ge‐Ning; Qi, Ting; Shi, Qinqin; Houk, K N; Huang, Hui (July 2025, Angewandte Chemie International Edition)

   Abstract The transition‐metal‐catalyzed Suzuki‐Miyaura cross‐coupling (SMC) reaction of organoboron nucleophiles with aryl (pseudo)halide electrophiles is a reliable method for carbon‐carbon bond formation. This reaction generally requires the use of an exogenous base to promote transmetalation process, which limits the substrate scope of the reaction due to undesired protodeboronation and functional group incompatibilities. Here, we established a base‐free SMC reaction via a conceptually different electrophilic substitution transmetalation (EST). This transformation is applicable to a wide range of base‐sensitive and sterically hindered organoborons. Key to this advance is the formation of a stable cationic palladium(II) or nickel(II) intermediate via experimental and theoretical investigations. In a broader context, this research further expands the synthetic boundary of cross‐coupling chemistry. 

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4. 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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5. Diastereoselective Synthesis of Aryl C ‐Glycosides from Glycosyl Esters via C−O Bond Homolysis

   https://doi.org/10.1002/anie.202014991  

   Wei, Yongliang; Ben‐zvi, Benjamin; Diao, Tianning (March 2021, Angewandte Chemie International Edition)

   Abstract C‐aryl glycosyl compounds offer better in vivo stability relative toO‐ andN‐glycoside analogues.C‐aryl glycosides are extensively investigated as drug candidates and applied to chemical biology studies. Previously,C‐aryl glycosides were derived from lactones, glycals, glycosyl stannanes, and halides, via methods displaying various limitations with respect to the scope, functional‐group compatibility, and practicality. Challenges remain in the synthesis ofC‐aryl nucleosides and 2‐deoxysugars from easily accessible carbohydrate precursors. Herein, we report a cross‐coupling method to prepareC‐aryl and heteroaryl glycosides, including nucleosides and 2‐deoxysugars, from glycosyl esters and bromoarenes. Activation of the carbohydrate substrates leverages dihydropyridine (DHP) as an activating group followed by decarboxylation to generate a glycosyl radical via C−O bond homolysis. This strategy represents a new means to activate alcohols as a cross‐coupling partner. The convenient preparation of glycosyl esters and their stability exemplifies the potential of this method in medicinal chemistry. 

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