Decatungstate-Catalyzed C(sp3)-H Alkylation of a Val Residue Proximal to the N-Terminus Controlled by an Electrostatic Interaction

Site-Selective C(sp3)-H Fluorination of Saccharides: Switching the Reaction Sites by Changing Fluorination Reagents and Hydrogen Atom Transfer Catalysts

We successfully developed a method for the site-selective C(sp3)-H fluorination of saccharides. When saccharides were treated with Selectfluor under 405 nm light irradiation, fluorination selectively proceeded at the weakest C(sp3)-H bond. Conversely, when the same saccharides were treated with N-fluorobenzenesulfonimide in the presence of a sodium decatungstate catalyst under 365 nm light irradiation, the reaction site could be switched and fluorination occurred at the C(sp3)-H bond with less steric hindrance.

Hollow mesoporous silica nanoparticles for drug formulation and delivery: Opportunities for cancer therapy

The advantages of large surface area, high volume ratio, good biocompatibility, and controllable surface functionalization make hollow mesoporous silica nanoparticles (HMSNs) an ideal drug carrier. HMSNs can achieve high efficiency, targeting, and controlled release by adjusting the microstructure and surface modification of its particles, which makes it broad application prospects in the field of medical therapy, especially in cancer therapy. Numerous studies have shown that preparation method, shape, particle size, hollow inner diameter, aperture and wall thickness of the HMSNs, the characteristics of the drugs, the interaction between the drugs and the carriers, and the external environment all closely affect the drug delivery, release, and efficacy. The external environment includes temperature, pH value, light intensity, magnetic field intensity, enzyme type and concentration, etc. This review summarizes the research progress of HMSNs as carrier materials in the past five years, analyzes the existing problems in the application process and presents the development prospects of HMSNs.

Design Approaches That Utilize Ionic Interactions to Control Selectivity in Transition Metal Catalysis

The attractive force between two oppositely charged ions can constitute a powerful design tool in selective catalysis. Enzymes make extensive use of ionic interactions alongside a variety of other noncovalent interactions; recent years have seen synthetic chemists begin to seriously explore these interactions in catalyst designs that also incorporate a reactive transition metal. In isolation, a single ionic interaction exhibits low directionality, but in many successful systems they exist alongside additional interactions which can provide a high degree of organization at the selectivity-determining transition state. Even in situations with a single key interaction, low directionality is not always detrimental, and can even be advantageous, conferring generality to a single catalyst. This Review explores design approaches that utilize ionic interactions to control selectivity in transition metal catalysis. It is divided into two halves: in the first, the ionic interaction occurs in the outer sphere of the metal complex, using a ligand which is charged or bound to an anion; in the second, the metal bears a formal charge, and the ionic interaction is with an associated counterion.

Hydrogen Bond-Controlled Site-Selective C(sp3)-H Alkylation of Sulfonanilides

We successfully developed a decatungstate-catalyzed benzylic C(sp3)-H alkylation of sulfonanilides by utilizing the hydrogen bond between the sulfonamide group of the substrates and decatungstate photocatalysts. Using this catalytic system, site-selective C(sp3)-H alkylation was achieved at the benzylic position near the sulfonamide group.

Methionine-enabled peptide modification through late-stage Pd-catalyzed β-C(sp3)-H olefination/cyclization

We present a method for site-selective diversification of peptides via Pd-catalyzed β-C(sp3)-H olefination/cyclization. In this protocol, the native methionine residue acts as a directing group, enabling site-specific olefination/cyclization of peptides. This chemistry demonstrates broad substrate scope, offering a versatile tool for peptide ligation.

Boronyl-Group-Assisted Decatungstate-Catalyzed Benzylic C(sp3)-H Alkylation

Boronic acid synthesis primarily involves the introduction of boronyl groups. However, an alternative route that involves the functionalization of boronic acids has not received much attention. This study describes the catalytic C(sp3)-H alkylation of ortho-tolylboronic acids utilizing the interaction between a free boronyl group [-B(OH)2] and a decatungstate photocatalyst [W10O32]4-. The boronyl groups of the alkylated products could be converted without isolation of the alkylated product.

Development and application of decatungstate catalyzed C-H 18F- and 19F-fluorination, fluoroalkylation and beyond

Over the past few decades, photocatalytic C-H functionalization reactions have received increasing attention due to the often mild reaction conditions and complementary selectivities to conventional functionalization processes. Now, photocatalytic C-H functionalization is a widely employed tool, supporting activities ranging from complex molecule synthesis to late-stage structure-activity relationship studies. In this perspective, we will discuss our efforts in developing a photocatalytic decatungstate catalyzed C-H fluorination reaction as well as its practical application realized through collaborations with industry partners at Hoffmann-La Roche and Merck, and extension to radiofluorination with radiopharmaceutical chemists and imaging experts at TRIUMF and the BC Cancer Agency. Importantly, we feel that our efforts address a question of utility posed by Professor Tobias Ritter in "Late-Stage Fluorination: Fancy Novelty or Useful Tool?" (ACIE, 2015, 54, 3216). In addition, we will discuss decatungstate catalyzed C-H fluoroalkylation and the interesting electrostatic effects observed in decatungstate-catalyzed C-H functionalization. We hope this perspective will inspire other researchers to explore the use of decatungstate for the purposes of photocatalytic C-H functionalization and further advance the exploitation of electrostatic effects for both rate acceleration and directing effects in these reactions.