Al(III)-Promoted Formation of All-Carbon Quaternary Centers from Aliphatic Tertiary Chlorides and Alkynyl Silanes

Despite the accessibility of numerous alkynes through coupling or substitution reactions, the synthesis of trialkyl-substituted alkynes is still a major challenge. Within this context, we reexplored the electrophilic alkynyl substitution between tertiary aliphatic chlorides and silylated alkynes. We were able to demonstrate that this approach is significantly more general than originally demonstrated by Capozzi and even tolerates several functional groups. Furthermore, we report diastereoselective reactions which in some instances gave excellent diastereoselectivity (dr >95:5).

Advancements in hydrochlorination of alkenes

The hydrochlorination of alkenes has been extensively studied in research and is commonly featured in organic chemistry textbooks as an exemplification of the Markovnikov rule. However, the application of this reaction is typically limited to specific alkenes, such as highly substituted ones, styrenes, or strained systems. Conversely, monosubstituted or 1,2-disubstituted alkenes do not readily react with HCl gas or solutions of HCl gas at practical rates. The challenges associated with hydrochlorination reactions for these "non-activated" alkenes have spurred considerable research efforts over the past 30 years, which constitute the primary focus of this review. The discussion begins with classical polar hydrochlorinations, followed by metal-promoted radical hydrochlorinations, and concludes with a brief overview of recent anti-Markovnikov hydrochlorinations.

Volumization of the young and the old temple using a highly cross-linked HA filler

BACKGROUND

A plethora of age-related changes contribute to hollowing of the temples, as bone remodeling, atrophy of the temporalis muscle, thinning of the skin, and deflation of the subcutaneous and deep temporal fat create the appearance of a skeletonized face. In addition, previous studies have established a relationship between facial skeletonization, temporal hollowing, and postmenopausal sarcopenia.

OBJECTIVE

To compare the volume change, adverse events, and patient satisfaction of soft-tissue filler injections in the temple between young (<51) and old (>51) females.

MATERIAL AND METHODS

A total of 30 women with a mean age of 53.1 ± 12.1 years underwent bilateral temporal volumization. Adverse events and satisfaction were assessed after 3 and 6 months. 3-Dimensional surface imaging was performed at baseline and after 2 weeks, 3 and 6 months to assess volumetric changes.

RESULTS

A mean volume of 5.55 ± 1.9 cc was injected into the temples. A total of 31 adverse events were observed in 13 patients. The overall satisfaction of the procedure was very high after 3 and 6 months in both patient groups, and raters showed a significant agreement in their assessment of the aesthetic improvement, while the self-reported patient satisfaction was also substantially high. The surface-volume coefficient differed significantly between 14 days and 3 months post-injection only in pre-menopausal patients, while no significant difference was detected between 3 and 6 months.

CONCLUSION

Temporal soft-tissue filler injections are safe and provide long-lasting aesthetic improvement both in pre- and postmenopausal women.

Expedient synthesis of conjugated triynes via alkyne metathesis

The first synthesis of conjugated triynes by molybdenum-catalysed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site-selective alkyne metathesis to produce the desired conjugated triyne products. The steric hindrance of the alkyne moiety was found to be crucial in preventing the formation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity.

The first synthesis of symmetrical and dissymmetrical conjugated triynes by self- and cross-metathesis was successfully achieved thanks to the use of hindered diynes.

A tutorial review of stereoretentive olefin metathesis based on ruthenium dithiolate catalysts

Stereoretentive olefin metathesis based on ruthenium dithiolate complexes has become a very active field of research within the past years. This unique catalyst class is able to kinetically produce both Z- and E-alkenes in high stereochemical purity (typically >95:5) starting from stereochemically pure Z- or E-alkenes. The aim of this tutorial review is to organize the reported information concerning ruthenium dithiolate catalysts in a logic manner, thus providing an "operators handbook" for chemists who wish to apply this methodology in synthesis.

Copper mediated carbometalation reactions

Since the first discovery of carbocupration of alkynes in the 1970s a tremendous amount of research has been carried out in this field. The exceptionally high selectivities obtained attribute to the great synthetic value of carbocupration reactions. This tutorial review will present the most important features of carbocupration of alkynes and highlight the most relevant reviews. Then a comprehensive review of copper mediated carbometalation of cyclopropenes will follow. The latter method has received much attention over the last decade as it allows the highly selective construction of poly-substituted cyclopropanes which can be transformed into acyclic derivatives bearing one or multiple tertiary or quaternary carbon stereocenters.

Mitogen-induced gamma interferon production in peripheral blood lymphocytes from patients with colorectal tumors

Mitogen-induced interferon production in peripheral blood lymphocytes from patients with colorectal tumors was not significantly different from that observed in patients with Crohn's disease and sex- and age-matched controls. In the group of patients with colorectal carcinomas, no correlation was obtained with regard to the interferon titer, the in vivo lymphocyte proliferation and the clinical stage of the disease or tumor staging and grading respectively. Most importantly, the data show that despite an obvious defect in T-lymphocyte proliferation, measurement of lymphokine production in mitogen-stimulated cell cultures was not impaired.