Enantioselective [4 + 2] Cycloaddition of <i>o</i>‑Quinone Methides and Vinyl Sulfides: Indirect Access to Generally Substituted Chiral Chromanes

A catalytic asymmetric [4 + 2] cycloaddition of <i>ortho</i>-quinone methides (<i>o</i>-QMs) is described. With the readily available vinyl sulfides as the key 2π partner and a properly chosen chiral phosphoric acid catalyst, the reaction proceeded under mild conditions to form the corresponding adduct with high enantio- and diastereoselectivity. Owning to the easy removal and conversion of the sulfenyl group in the product, the present process provides indirect access to generally substituted chromanes previously lacking easy access. Mechanistically, the reaction is also a new demonstration of the rarely achieved sole activation of <i>o</i>-QM for asymmetric control

Enantioselective [4 + 2] Cycloaddition of <i>o</i>‑Quinone Methides and Vinyl Sulfides: Indirect Access to Generally Substituted Chiral Chromanes

A catalytic asymmetric [4 + 2] cycloaddition of <i>ortho</i>-quinone methides (<i>o</i>-QMs) is described. With the readily available vinyl sulfides as the key 2π partner and a properly chosen chiral phosphoric acid catalyst, the reaction proceeded under mild conditions to form the corresponding adduct with high enantio- and diastereoselectivity. Owning to the easy removal and conversion of the sulfenyl group in the product, the present process provides indirect access to generally substituted chromanes previously lacking easy access. Mechanistically, the reaction is also a new demonstration of the rarely achieved sole activation of <i>o</i>-QM for asymmetric control

Catalytic Asymmetric α‑Aldol Reaction of Vinylogous <i>N</i>‑Heterocyclic Carbene Enolates: Formation of Quaternary and Labile Tertiary Stereocenters

Simple <i>N</i>-heterocyclic carbene (NHC)-enolates are widely studied versatile species. However, their vinylogous siblings (i.e., vinylogous NHC-enolates) have been much less studied. Here we disclose the first catalytic asymmetric α-aldol reaction of vinylogous NHC-enolates. With trifluoropyruvate as the carbon electrophile, the efficient C–C bond formation process displays not only complete α-regioselectivity but also excellent stereocontrol over the two newly established challenging stereocenters (one quaternary and the other labile tertiary), furnishing a range of highly enantioenriched β,γ-unsaturated α-fluoroalkylated esters

A New Strategy for Efficient Synthesis of Medium and Large Ring Lactones without High Dilution or Slow Addition

We have developed an efficient method for medium and large ring lactone synthesis by a conceptually different ring-expansion strategy. The design of an unprecedented ring conjunction mode of oxetene, combined with the appropriate choice of a Lewis acid promoter and an additive, constitutes the key components of the new process. Enabled by this new approach, the reaction does not require high dilution or slow addition

Organocatalytic Asymmetric Nucleophilic Addition to <i>o</i>‑Quinone Methides by Alcohols

The first catalytic asymmetric intermolecular alcohol conjugate addition to <i>o</i>-quinone methides (<i>o</i>-QMs) is disclosed. Due to reversible C–O bond formation and low nucleophilicity of alcohols, catalytic asymmetric oxa-Michael additions with simple alcohol nucleophiles to establish acyclic oxygenated carbon stereocenters remain scarce. The present reaction represents a rare example of this type. With a suitable chiral acid catalyst, the in situ formation of <i>o</i>-QMs and subsequent conjugate addition proceeded with high efficiency and enantioselectivity. The chiral ether products are versatile precursors to other chiral molecules

Surfactant-Free, Large-Scale, Solution–Liquid–Solid Growth of Gallium Phosphide Nanowires and Their Use for Visible-Light-Driven Hydrogen Production from Water Reduction

Colloidal GaP nanowires (NWs) were synthesized on a large scale by a surfactant-free, self-seeded solution–liquid–solid (SLS) method using triethylgallium and tris(trimethylsilyl)phosphine as precursors and a noncoordinating squalane solvent. Ga nanoscale droplets were generated in situ by thermal decomposition of the Ga precursor and subsequently promoted the NW growth. The GaP NWs were not intentionally doped and showed a positive open-circuit photovoltage based on photoelectrochemical measurements. Purified GaP NWs were used for visible-light-driven water splitting. Upon photodeposition of Pt nanoparticles on the wire surfaces, significantly enhanced hydrogen production was observed. The results indicate that colloidal surfactant-free GaP NWs combined with potent surface electrocatalysts could serve as promising photocathodes for artificial photosynthesis

A New Strategy for Efficient Synthesis of Medium and Large Ring Lactones without High Dilution or Slow Addition

We have developed an efficient method for medium and large ring lactone synthesis by a conceptually different ring-expansion strategy. The design of an unprecedented ring conjunction mode of oxetene, combined with the appropriate choice of a Lewis acid promoter and an additive, constitutes the key components of the new process. Enabled by this new approach, the reaction does not require high dilution or slow addition

Chiral Phosphoric Acid Catalyzed Enantioselective Desymmetrization of <i>meso</i>-Epoxides by Thiols

The first chiral Brønsted acid catalyzed asymmetric nucleophilic ring-opening reaction of <i>meso</i>-epoxides is described. In the presence of TRIP, a range of <i>meso</i>-epoxides could undergo smooth ring-opening reactions by aryl thiols with good efficiency and enantioselectivity

Catalyst-Controlled Divergent Reactions of 2,3-Disubstituted Indoles with Propargylic Alcohols: Synthesis of 3<i>H</i>‑Benzo[<i>b</i>]azepines and Axially Chiral Tetrasubstituted Allenes

Catalyst-controlled divergent reactions of 2,3-disubstituted indoles with propargylic alcohols were developed for the first time. In the presence of TsOH or B(C6F5)3 as catalyst, 2,3-disubstituted indoles reacted smoothly with 3-alkynyl-3-hydroxyisoindolinones to afford 3H-benzo[b]azepines by selective C2(sp2)–C3(sp2) ring expansion of indoles. In contrast, decreasing the catalyst strength (e.g., with chiral phosphoric acid) interrupted the cascade reactions, affording axially chiral tetrasubstituted allenes bearing an adjacent chiral quaternary carbon stereocenter. Control experiments provided insights into the reaction mechanism

DataSheet1_Nanotechnological advances in cancer: therapy a comprehensive review of carbon nanotube applications.PDF

Nanotechnology is revolutionising different areas from manufacturing to therapeutics in the health field. Carbon nanotubes (CNTs), a promising drug candidate in nanomedicine, have attracted attention due to their excellent and unique mechanical, electronic, and physicochemical properties. This emerging nanomaterial has attracted a wide range of scientific interest in the last decade. Carbon nanotubes have many potential applications in cancer therapy, such as imaging, drug delivery, and combination therapy. Carbon nanotubes can be used as carriers for drug delivery systems by carrying anticancer drugs and enabling targeted release to improve therapeutic efficacy and reduce adverse effects on healthy tissues. In addition, carbon nanotubes can be combined with other therapeutic approaches, such as photothermal and photodynamic therapies, to work synergistically to destroy cancer cells. Carbon nanotubes have great potential as promising nanomaterials in the field of nanomedicine, offering new opportunities and properties for future cancer treatments. In this paper, the main focus is on the application of carbon nanotubes in cancer diagnostics, targeted therapies, and toxicity evaluation of carbon nanotubes at the biological level to ensure the safety and real-life and clinical applications of carbon nanotubes.</p