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1. Catalytic reduction of aryl trialkylammonium salts to aryl silanes and arenes

   https://doi.org/10.1039/c9sc01083a  

   Rand, Alexander W.; Montgomery, John (January 2019, Chemical Science)

   A new approach for the reduction of aryl ammonium salts to arenes or aryl silanes using nickel catalysis is reported. This method displays excellent ligand-controlled selectivity based on the N-heterocyclic carbene (NHC) ligand employed. Utilizing a large NHC in non-polar solvents generates aryl silanes, while small NHCs in polar solvents promote reduction to arenes. Several classes of aryl silanes can be accessed from simple aniline building blocks, including those useful for cross-couplings, oxidations, and halogenations. The reaction conditions are mild, functional group tolerant, and provide efficient access to a variety of benzene derivatives. 

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2. On-resin Cα-functionalization of N -arylglycinyl peptides with boronic acids

   https://doi.org/10.1039/d2ob00524g  

   Young, Hailey A.; Proulx, Caroline (August 2022, Organic & Biomolecular Chemistry)

   A late-stage α-C–H functionalization reaction of resin-bound, electron-rich N -aryl peptides with boronic acid nucleophiles under mild conditions is reported. We explore the impact of the N -arylglycinyl peptide structure on reactivity, and present a scope of the optimized reaction where both the peptide sequence and nature of boronic acid derivatives are varied. 

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3. Photochemistry of N ‐aryl and N ‐alkyl dibenzothiophene sulfoximines

   https://doi.org/10.1111/php.13978  

   Throgmorton, John C; Iverson, Alexis J; McCulla, Ryan D (June 2024, Photochemistry and Photobiology)

   Abstract N‐phenyl dibenzothiophene sulfoximine has been demonstrated to produce phenyl nitrene and dibenzothiopheneS‐oxide upon irradiation with UV‐A light, and dibenzothiopheneS‐oxide upon further irradiation releases triplet atomic oxygen. Thus,N‐phenyl dibenzothiophene sulfoximine exhibits a rare dual‐release capability in its photochemistry. In this work,N‐substituted dibenzothiophene sulfoximine derivatives are irradiated with UV‐A light to compare their photochemistry and quantum yield of dibenzothiopheneS‐oxide production with that ofN‐phenyl dibenzothiophene sulfoximine. BothN‐aryl andN‐alkyl derivatives of dibenzothiophene sulfoximine are examined to observe their effects on the quantum yield of the photolysis reaction. Adding electron withdrawingN‐aryl substituents is shown to increase the quantum yield of dibenzothiopheneS‐oxide production, while adding electron donatingN‐aryl substituents is shown to decrease the quantum yield. The quantum yield was slightly lowered or not increased by mostN‐alkyl substituents. Furthermore, the quantum yield was not augmented by branching and steric hindrance effects associated with theN‐alkyl substituents. These results suggest that electronic modulation of the sulfoximine bonds affects the observed photolysis reaction. 

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4. Synthesis of α‐Sulfonyl Ketones through a Salicylic Acid‐Catalyzed Multicomponent Reaction Involving Arylsulfonation and Oxidation

   https://doi.org/10.1002/slct.202104138  

   Sakkani, Nagaraju; Jakkampudi, Satish; Sadiq, Nouraan; Zhao, John C. ‐G. (December 2021, ChemistrySelect)

   Abstract The direct synthesis of α‐sulfonyl ketones was accomplished by a multicomponent reaction of styrene derivatives, anilines,t‐butyl nitrite, 1,4‐diazabicyclo[2.2.2]octane‐sulfur dioxide (DABSO), and oxygen catalyzed by salicylic acid. The aryl radicals generated from aniline derivatives andt‐butyl nitrite under the catalysis of salicylic acid was sulfonylated by DABSO to generate the arylsulfonyl radicals, which reacted further with styrenes, and then oxidized by oxygen to give the title compounds. Under the optimized conditions, the title compounds were obtained in good yields at ambient temperature within 1.5–2 h. 

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5. Synthesis of Sterically Congested Carbamates of Carbohydrates through Organic Base Catalysis

   https://doi.org/10.1055/s-0037-1612425  

   Chen, Anji; Wang, Dan; Samankumara, Lalith; Wang, Guijun (April 2019, Synthesis)

   4,6-O-Benzylidene acetal protected α-methoxy d-glucose and d-glucosamine are useful building blocks for the syntheses of carbohydrate derivatives and functional molecular assemblies. In this research, we have developed a general method for the preparation of C-3 carbamate derivatives of densely functionalized glucose and glucosamine with isocyanates using organic bases as catalysts. Without a suitable catalyst, the C-3 hydroxy group of the glucosamine derivative could not be converted into the corresponding carbamates when treated with isocyanates. Several organic bases were screened as the catalysts for the reactions, and we discovered that 5.0 mol% of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was an effective catalyst for the carbamoylation reaction. A library of both alkyl and aryl carbamate derivatives of the two sterically congested carbohydrates have been effectively synthesized using the current method. 

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