Catalytic Epoxidation of Carbonyl Compounds via Carbonyl Ylides: from Racemic to Enantioselective.

Transition metal-catalyzed epoxidation of carbonyl compounds through carbonyl ylides represents a highly effective method for synthesizing a diverse range of valuable epoxides. This review offers an in-depth overview of the latest developments in inter- and intramolecular epoxidation reactions involving metal carbenes and carbonyl compounds, encompassing both racemic to enantioselective transformations. These catalytic epoxidations are reviewed by highlighting their product selectivity, diversity and applicability, and the related mechanistic rationale is showcased where possible.

Asymmetric formal C-C bond insertion into aldehydes via copper-catalyzed diyne cyclization.

The formal C-C bond insertion into aldehydes is an attractive methodology for the assembly of homologated carbonyl compounds. However, the homologation of aldehydes has been limited to diazo approach and the enantioselective reaction was rarely developed. Herein, we report an asymmetric formal C-C bond insertion into aldehydes through diyne cyclization strategy.

Enantioselective Copper-Catalyzed Formal [2+1] and [4+1] Annulations of Diynes with Ketones via Carbonyl Ylides.

Carbonyl ylides have proven to be powerful synthons for the efficient construction of various valuable O-heterocycles, and the formation of carbonyl ylides by the reaction of metal carbenes with carbonyls has attracted increasing attention over the past decades. However, a catalyst-controlled highly enantioselective reaction of carbonyl ylides from metal carbenes is extremely challenging. Herein, we report a novel copper-catalyzed asymmetric formal [2+1] and [4+1] annulations of diynes with ketones via carbonyl ylides.

Effects of surgical periodontal therapy on serum levels of TNF-alpha in patients with chronic periodontitis.

Aim: To find if serum levels of tumor necrosis factor-alpha (TNF-alpha) can change after a surgical periodontal treatment.

Patients And Methods: Moderate to severe periodontitis subjects who received basic periodontal treatment were included in the study and randomly divided into two groups. In group A, periodontal surgery was performed.

Effect of non-surgical periodontal therapy on patients with type 2 diabetes mellitus.

Unlabelled: The AIM of this study was to evaluate the effect of non-surgical therapy on clinical variables and glycemic control on type 2 diabetics with chronic periodontitis.

Patients And Methods: Forty six type 2 diabetics with chronic periodontitis were randomized into two groups (group A and group B). Treatment included scaling and root planning for group A plus systematic use of doxycycline in both groups.

[Root canal therapy of resinified teeth with surgical operating microscope and ultrasonic instruments].

Purpose: To evaluate the role of surgical operating microscope and ultrasonic instruments in endodontic treatment of patients who underwent previous resinifying therapy.

Methods: 63 premolars and molars that had been treated with resinifying therapy before were selected for root canal therapy. The coronal portion of resinified root canals were negotiated with ultrasonic instruments under surgical operating microscope, and the apical portion was managed with small size hand files and 15% EDTA.

[Treatment of teeth with open apices using mineral trioxide aggregate as apical barrier].

Purpose: To evaluate the clinical effect of treatment of teeth with open apices using mineral trioxide aggregate (MTA) as apical barrier under surgical operating microscope.

Methods: The root canals of 23 teeth with open apices were cleaned and shaped, and disinfected with calcium hydroxide. The MTA mixture were then carried into the apical part of the root canals to create a 3-5 mm apical barrier.

[Clinical evaluation of nickel-titanium rotary instruments Hero 642 in root canal preparation].

Purpose: This research is aimed to assess the clinical value of the Nickel-titanium (NiTi) rotary instruments Hero 642 in root canal preparation.

Methods: 60 molars were instrumented by Hero 642 rotary instruments using crown-down technique in the experimental group, and by K files using step-back technique in the control group. All teeth were obturated with lateral condensation method.