Expression of concern: SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN).

Expression of concern for 'SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN)' by Yiyong Zhao et al., RSC Adv., 2020, 10, 17288-17292, DOI: https://doi.org/10.1039/D0RA02631J.

Expression of concern: A cascade process for directly converting nitriles (RCN) to cyanamides (RNHCN) via SO2F2-activated Tiemann rearrangement.

Expression of concern for 'A cascade process for directly converting nitriles (RCN) to cyanamides (RNHCN) via SO2F2-activated Tiemann rearrangement' by Guofu Zhang et al., Org. Biomol. Chem., 2019, 17, 7684-7688, https://doi.org/10.1039/C9OB01547G.

SO2F2-Mediated Fluorination of P(O)-H and P(O)-OH Compounds under Mild Conditions.

With the increasing relevance of organophosphorus fluorine compounds in the pharmaceutical industry, their synthesis has attracted great attention. Herein, we report an efficient fluorination strategy for P(O)-H and P(O)-OH compounds using sulfuryl fluoride as the fluorination reagent. Avoiding the use of expensive or complex prepreparation reagents for fluoridation, this strategy could conveniently construct a variety of fluorophosphonates and phosphonofluoridates under mild conditions and without additional oxidants.

Nickel-Catalyzed Selective C-H Cyanation via Aromatic Thianthrenium Salts.

Here, we report the first case of nickel-catalyzed C-H cyanation via arylthianthrenium salts. The reaction features the use of air-stable and inexpensive NiCl2·6H2O as a catalyst for the highly selective construction of cyanation products by aromatic pre-thianthrenation. The mechanism study shows that the formation of aryl radicals is involved. Also, this protocol can be applied to the late-stage functionalization of bioactive molecules and is readily scalable, further showcasing the synthetic utility.

The stable "F-SO2 +" donor provides a mild and efficient approach to nitriles and amides.

In this update, we developed a mild, efficient and practical method using fluorosulfuryl imidazolium salt A as an environment friendly promoter for conversion of oximes to nitriles or amides via ß-elimination or Beckmann rearrangement in almost quantitative yield in 10 minutes. The target products were generated in gram-scale and could be collected through crystallization without silica gel column purification in excellent yield.

A late-stage functionalization tool: sulfonyl fluoride mediated deoxymethylation of phenols.

The late-stage functionalization of drugs and natural products has been identified as a promising approach to accelerate the discovery of new bioactive compounds. Due to the presence of the "Magic Methyl Effect", the direct deoxymethylation of phenolic hydroxyl groups, which are widespread in natural molecules, is a challenging task. A mild and rapid strategy for direct phenol deoxymethylation under metal catalysis using SO2F2 is described in this paper, while good functional group tolerance and high chemoselectivity allow this strategy to be one of the powerful tools for LSF. The power of this new platform is showcased through gram-scale and orthogonal experiments.

Palladium-Catalyzed Direct Decarbonylative Cyanation of Aryl Carboxylic Acids.

The direct transformation of aryl carboxylic acids to aryl nitrile compounds is an interesting topic because carboxylic acids are not only abundant in nature but are also inexpensive and stable. Here, the synthesis of a series of aryl nitriles by palladium-catalyzed decarbonylative cyanation of carboxylic acids without base has been achieved. The successful decarbonylative cyanation of drug molecules and Gram-scale reaction to verify the practicality and operability of this method are analyzed.

In Situ Hydrogen Peroxide Production for Selective Oxidation of Benzyl Alcohol over a Pd@Hierarchical Titanium Silicalite Catalyst.

Using in situ generated H2O2 is potentially an effective approach for benzyl alcohol selective oxidation. While the microporous titanium silicate (TS-1) supported with Pd is promising for selective oxidation, the Pd particles are preferentially anchored on the external surface, which leads to the problems such as non-uniform dispersion and low thermal stability. Here, we prepared a Pd@HTS-1 catalyst in which the Pd subnanoparticles were encapsulated in the channels of the hierarchical TS-1 (HTS-1), for benzyl alcohol selective oxidation with in situ produced H2O2. We find that the oxidation rate of benzyl alcohol by in situ H2O2 over the Pd@HTS-1 is up to 4268.8 mmol h-1 kgcat -1, and the selectivity of benzaldehyde approaches 100%. In contrast to the conventional Pd/HTS-1, the present Pd@HTS-1 benefits the benzyl alcohol selective oxidation due to the increased dispersion of Pd particles (forming uniformly dispersed subnano-sized particles), as well as the confinement effect and hierarchical porosity of the HTS-1 host. We further suggested that hydrogen peroxide produced in situ from the molecular hydrogen and oxygen over the Pd sites can be spilled over to the framework Ti4+ sites, forming the Ti-OOH active species, which selectively oxidizes the chemisorbed benzyl alcohol to benzaldehyde on the Pd sites.

SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN).

A simple, mild and practical cascade process for the direct conversion of aldehydes to cyanamides was developed featuring a wide substrate scope and great functional group tolerability. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable cyanamides in a pot, atom, and step-economical manner with a green nitrogen source. This protocol will serve as a robust tool for the installation of the cyanamide moiety in various complicated molecules.

A cascade process for directly converting nitriles (RCN) to cyanamides (RNHCN) via SO2F2-activated Tiemann rearrangement.

A simple, mild and practical process for the direct conversion of nitriles to cyanamides was newly discovered and exhibited a wide substrate scope as well as great functional group-tolerability (36 examples). In this efficient strategy, the in situ generated amidoximes obtained from the reaction of nitriles with hydroxylamine subsequently underwent Tiemann rearrangement, producing the corresponding cyanamides with great isolated yields under SO2F2. Additionally, the control experiments reportedly shed light on the tentative mechanism involved in the formation and elimination of the key intermediate: a sulfonyl ester.

Highly efficient hydrogen peroxide direct synthesis over a hierarchical TS-1 encapsulated subnano Pd/PdO hybrid.

We report a hierarchical TS-1 encapsulated subnano Pd/PdO hybrid catalyst that shows unprecedented activity in H2O2 direct synthesis from H2 and O2. The macro reaction rate in 30 min is up to 35 010 mmol gPd -1 h-1 at ambient temperature. Such high catalytic activity is achieved due to the hierarchical porous structure of TS-1 and the formation of the encapsulated subnano Pd/PdO hybrid after oxidation/reduction/oxidation treatment.

NH3⋠H2O: The Simplest Nitrogen-Containing Ligand for Selective Aerobic Alcohol Oxidation to Aldehydes or Nitriles in Neat Water.

Aqueous ammonia (NH3⋅H2O) has been shown to serve as the simplest nitrogen-containing ligand to effectively promote copper-catalyzed selective alcohol oxidation under air in water. A series of alcohols with varying electronic and steric properties were selectively oxidized to aldehydes with up to 95 % yield. Notably, by increasing the amount of aqueous ammonia in neat water, the exclusive formation of aryl nitriles was also accomplished with good-to-excellent yields. Additionally, the catalytic system exhibits a high level of functional group tolerance with -OH, -NO2, esters, and heteroaryl groups all being amenable to the reaction conditions. This one-pot and green oxidation protocol provides an important synthetic route for the selective preparation of either aldehydes or nitriles from commercially available alcohols.

Ru-Catalyzed Regioselective Direct Hydroxymethylation of (Hetero)Arenes via C-H Activation.

An efficient and direct ruthenium-catalyzed regioselective hydroxymethylation of (hetero)arenes via C-H activation with paraformaldehyde as a hydroxymethylating reagent is described. The corresponding products can be obtained in good to excellent yield. A number of aryl aldehydes can also be used in place of paraformaldehyde giving the desired alcohol products with similarly good results.

Pd(II)-catalyzed C(sp(3))-H arylation of amino acid derivatives with click-triazoles as removable directing groups.

By using click-triazoles as conveniently approachable and removable directing groups, the direct palladium-catalyzed C(sp(3))-H arylation of amino acid derivatives with various aryl iodides bearing different electronic properties has been achieved. Notably, the desired amino acid molecule can be obtained by the cleavage of the tethered click-triazoles after the catalytic reaction, which aims to provide a practical protocol for the accessibility of both natural and synthetic amino acids.

L-Proline: an efficient N,O-bidentate ligand for copper-catalyzed aerobic oxidation of primary and secondary benzylic alcohols at room temperature.

A novel and highly practical copper-catalyzed aerobic alcohol oxidation system with L-proline as the ligand at room temperature has been developed. A wide range of primary and secondary benzylic alcohols tested have been smoothly transformed into corresponding aldehydes and ketones with high yields and selectivities.

Highly selective Wacker reaction of styrene derivatives: a green and efficient aerobic oxidative process promoted by benzoquinone/NaNO2/HClO4 under mild conditions.

A green and efficient catalytic redox system for the aerobic oxidative Wacker oxidation of styrene derivatives at room temperature using molecular oxygen as the terminal oxidant without copper chloride has been developed. The newly developed system exhibited excellent catalytic activity for the smooth transformation of terminal styrene derivatives to the desired methyl ketones with up to 96% yield and >99% selectivity.

Dual-functional click-triazole: a metal chelator and immobilization linker for the construction of a heterogeneous palladium catalyst and its application for the aerobic oxidation of alcohols.

A novel SBA-15 supported catalyst PdL(n)@SBA-15 containing a 2-pyridyl-1,2,3-triazole ligand framework was prepared via a "click" route, in which the click-triazole acted as both a stable linker and a good chelator. The catalyst was characterized and applied for the aerobic oxidation of alcohols, and the product was obtained in up to 98% yield.

Sodium nitrite catalyzed aerobic oxidative deoximation under mild conditions.

A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO(2) as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO(2), can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications.

1,4-Diazabicyclo[2.2.2]octane-1,4-diium trichromate.

The title compound, (C(6)H(14)N(2))[Cr(3)O(10)], consists of a diazabicyclo[2.2.2]octane-1,4-diium cation and a discrete trichromate anion linked by an N-H.O hydrogen bond. Three CrO(4) tetrahedra are joined via shared O atoms to form the trichromate anion. Supramolecular rings, which can be described by the graph-set motif R(4)(4)(26), are built via N-H.O hydrogen bonds, and C-H.O interactions play lesser roles in forming the structure.