Palladium-Catalyzed Alkoxycarbonylation of Alcohols for the Synthesis of Cyclobutanecarboxylates with α-Quaternary Carbon Centers.

A palladium-catalyzed alkoxycarbonylation with two different alcohols for the synthesis of cyclobutanecarboxylates bearing an α-quaternary carbon center is presented. The reaction utilizes readily accessible starting materials, tolerates a broad scope of functional groups, and provides a straightforward and efficient approach for the synthesis of a diverse array of cyclobutanecarboxylates bearing an α-quaternary carbon. Meanwhile, this strategy effectively prevents the transition-metal-catalyzed ring-opening of cyclobutanols, preserves the cyclobutane framework, and affords 1,1-disubstituted cyclobutanecarboxylates in high yields with excellent regioisomeric ratios.

Palladium-Catalyzed Carbonylative Sonogashira Coupling of Aliphatic Alkynes and Aryl Thianthrenium Salts to Alkynones and Furanones.

Herein, we developed a mild and efficient palladium-catalyzed carbonylative Sonogashira coupling of aryl thianthrenium salts with aliphatic alkynes and benzyl acetylene toward alkynones and furanones. Various desired products were prepared in good yields with broad functional group tolerance including the bromide group. In the case of using benzyl acetylene, the corresponding furanones can be obtained in good yields under the same conditions with two molecules of CO inserted.

Ligand-controlled regiodivergent aminocarbonylation of cyclobutanols toward 1,1- and 1,2-substituted cyclobutanecarboxamides.

Four-membered carbocycles are among the most sought-after backbones which are commonly found in biologically active molecules. However, difficulties on their producing are existing due to its highly strained ring system. On the other hand, cyclobutanols can be straightforwardly prepared and can serves as precursors for synthesizing cyclobutane derivatives.

Palladium-Catalyzed Carbonylative Sonogashira Coupling of Aryl Thianthrenium Salts with Arylalkynes.

Alkynones are valuable compounds with applications in various areas. In this work, we developed an efficient carbonylation procedure for the carbonylative cross-coupling of aryl thianthrenium salts with aromatic alkynes. Various useful alkynones were produced in moderate to excellent yields under mild conditions.

Primary closure combined with C-tube drainage through cystic duct after laparoscopic common bile duct exploration is safe and feasible for patients.

Objective: Biliary duct management is of great significance after laparoscopic cholecystectomy (LC) combined with laparoscopic common bile duct exploration (LCBDE) in the treatment of cholecystolithiasis accompanied with common bile duct (CBD) stones. This study is to evaluate the safety and effectiveness of primary closure with C-tube drainage through cystic duct after LC + LCBDE.

Methods: Through a retrospective study, 290 patients who underwent LC + LCBDE in our hospital from January 2019 to April 2022 were enrolled and divided into 2 groups.

Comparing bariatric surgery and medical therapy for obese adolescents with type 2 diabetes.

Background: Mounting evidence in recent years has demonstrated that the number of obese adolescents has continued to rise. Obese adolescents are more likely to be diagnosed with type 2 diabetes, which causes additional harm. This study aimed to compare the clinical outcomes of bariatric surgery and medical treatment.

Copper-Catalyzed 1,2-Dicarbonylative Cyclization of Alkenes with Alkyl Bromides via Radical Cascade Process.

Herein, we developed a new procedure on 1,2-dicarbonylative cyclization of 4-aryl-1-butenes with alkyl bromides. Using simple copper catalyst, two molecules of carbon monoxide were introduced into the double bond with the formation of four new C-C bonds and a new ring. Various α-tetralones and 2,3-dihydroquinolin-4-ones were formed in moderate to good yields.

Enantioselective palladium-catalyzed C(sp)-C(sp) σ bond activation of cyclopropenones by merging desymmetrization and (3 + 2) spiroannulation with cyclic 1,3-diketones.

Catalytic asymmetric variants for functional group transformations based on carbon-carbon bond activation still remain elusive. Herein we present an unprecedented palladium-catalyzed (3 + 2) spiro-annulation merging C(sp)-C(sp) σ bond activation and click desymmetrization to form synthetically versatile and value-added oxaspiro products. The operationally straightforward and enantioselective palladium-catalyzed atom-economic annulation process exploits a TADDOL-derived bulky P-ligand bearing a large cavity to control enantioselective spiro-annulation that converts cyclopropenones and cyclic 1,3-diketones into chiral oxaspiro cyclopentenone-lactone scaffolds with good diastereo- and enantio-selectivity.

Stereospecific Si-C coupling and remote control of axial chirality by enantioselective palladium-catalyzed hydrosilylation of maleimides.

Hydrosilylation of unsaturated carbon-carbon bonds with hydrosilanes is a very important process to access organosilicon compounds and ranks as one of the most fundamental reactions in organic chemistry. However, catalytic asymmetric hydrosilylation of activated alkenes and internal alkenes has proven elusive, due to competing reduction of carbon-carbon double bond or isomerization processes. Herein, we report a highly enantioselective Si-C coupling by hydrosilylation of carbonyl-activated alkenes using a palladium catalyst with a chiral TADDOL-derived phosphoramidite ligand, which inhibits O-hydrosilylation/olefin reduction.

Controllable Si-C Bond Activation Enables Stereocontrol in the Palladium-Catalyzed [4+2] Annulation of Cyclopropenes with Benzosilacyclobutanes.

A novel and unusual palladium-catalyzed [4+2] annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si-C(sp ) bond activation in synergy with ring expansion/insertion of cyclopropenes to form new C(sp )-C(sp ) and Si-C(sp ) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo[4.

Prognostic value of miRNA-181a/b in colorectal cancer: a meta-analysis.

Aims: miR-181a and miR-181b have been investigated as prognostic biomarkers of colorectal cancer (CRC). However, there is controversy about the role of miR-181a and miR-181b in predicting CRC prognosis. Therefore, we performed this meta-analysis to evaluate prognostic values of miR-181a and miR-181b in CRC patients.

Triptycene: no homoconjugation effect for extending optical properties of π-conjugated oligomers.

1,5- and 1,8-bis(bifluorenyl)anthracene were synthesized and converted to their corresponding bis(bifluorenyl)triptycenes and bis(bifluorenyl)-9,10-dihydroanthracenes. Analysis of their optical properties shows no feature of extended conjugation in the triptycene pair. The electronic spectra of the triptycene and dihydroanthracene pairs are in fact superimposable.