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1. C11Tester: A race detector for C/C++ atomics

   https://doi.org/10.1145/3445814.3446711  

   Luo, Weiyu; Demsky, Brian (April 2021, Proceedings of the 26th ACM International Conference on Architectural Support for Programming Languages and Operating Systems)

   null (Ed.)

   Writing correct concurrent code that uses atomics under the C/C++ memory model is extremely difficult. We present C11Tester, a race detector for the C/C++ memory model that can explore executions in a larger fragment of the C/C++ memory model than previous race detector tools. Relative to previous work, C11Tester's larger fragment includes behaviors that are exhibited by ARM processors. C11Tester uses a new constraint-based algorithm to implement modification order that is optimized to allow C11Tester to make decisions in terms of application-visible behaviors. We evaluate C11Tester on several benchmark applications, and compare C11Tester's performance to both tsan11rec, the state of the art tool that controls scheduling for C/C++; and tsan11, the state of the art tool that does not control scheduling. 

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2. Tandem dehydrogenation-olefination-decarboxylation of cycloalkyl carboxylic acids via multifold C–H activation

   https://doi.org/10.1038/s41467-024-49359-x  

   Pal, Tanay; Ghosh, Premananda; Islam, Minhajul; Guin, Srimanta; Maji, Suman; Dutta, Suparna; Das, Jayabrata; Ge, Haibo; Maiti, Debabrata (June 2024, Nature Communications)

   Abstract Dehydrogenation chemistry has long been established as a fundamental aspect of organic synthesis, commonly encountered in carbonyl compounds. Transition metal catalysis revolutionized it, with strategies like transfer-dehydrogenation, single electron transfer and C–H activation. These approaches, extended to multiple dehydrogenations, can lead to aromatization. Dehydrogenative transformations of aliphatic carboxylic acids pose challenges, yet engineered ligands and metal catalysis can initiate dehydrogenation via C–H activation, though outcomes vary based on substrate structures. Herein, we have developed a catalytic system enabling cyclohexane carboxylic acids to undergo multifold C–H activation to furnish olefinated arenes, bypassing lactone formation. This showcases unique reactivity in aliphatic carboxylic acids, involving tandem dehydrogenation-olefination-decarboxylation-aromatization sequences, validated by control experiments and key intermediate isolation. For cyclopentane carboxylic acids, reluctant to aromatization, the catalytic system facilitates controlled dehydrogenation, providing difunctionalized cyclopentenes through tandem dehydrogenation-olefination-decarboxylation-allylic acyloxylation sequences. This transformation expands carboxylic acids into diverse molecular entities with wide applications, underscoring its importance. 

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3. Mesh: compacting memory management for C/C++ applications

   https://doi.org/10.1145/3314221.3314582  

   Powers, Bobby; Tench, David; Berger, Emery D.; McGregor, Andrew (January 2019, PLDI 2019)

   Programs written in C/C++ can suffer from serious memory fragmentation, leading to low utilization of memory, de- graded performance, and application failure due to memory exhaustion. This paper introduces Mesh, a plug-in replace- ment for malloc that, for the first time, eliminates fragmen- tation in unmodified C/C++ applications. Mesh combines novel randomized algorithms with widely-supported virtual memory operations to provably reduce fragmentation, break- ing the classical Robson bounds with high probability. Mesh generally matches the runtime performance of state-of-the- art memory allocators while reducing memory consumption; in particular, it reduces the memory of consumption of Fire- fox by 16% and Redis by 39%. 

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4. Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Aryl Chlorobenzoates with Alkyl Grignard Reagents

   https://doi.org/10.3390/molecules25010230  

   Bisz, Elwira; Szostak, Michal (January 2020, Molecules)

   Aryl benzoates are compounds of high importance in organic synthesis. Herein, we report the iron-catalyzed C(sp2)–C(sp3) Kumada cross-coupling of aryl chlorobenzoates with alkyl Grignard reagents. The method is characterized by the use of environmentally benign and sustainable iron salts for cross-coupling in the catalytic system, employing benign urea ligands in the place of reprotoxic NMP (NMP = N-methyl-2-pyrrolidone). It is notable that high selectivity for the cross-coupling is achieved in the presence of hydrolytically-labile and prone to nucleophilic addition phenolic ester C(acyl)–O bonds. The reaction provides access to alkyl-functionalized aryl benzoates. The examination of various O-coordinating ligands demonstrates the high activity of urea ligands in promoting the cross-coupling versus nucleophilic addition to the ester C(acyl)–O bond. The method showcases the functional group tolerance of iron-catalyzed Kumada cross-couplings. 

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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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