Iridium-catalysed thioether-directed regioselective cycloaddition of internal alkynes with azides.

We report herein a cationic iridium-catalysed thioether-directed alkyne-azide cycloaddition reaction. Diverse 2-alkynyl phenyl sulfides can undergo cycloaddition with different azides in a regioselective fashion. The reaction features high efficiency, a short reaction time, and a broad substrate scope, providing modular access to complex S-containing triazoles.

Z-Selective access to α-trifluoromethyl arylenes through Pd-catalysed fluoroarylation of 1,1-difluoroallenes.

The synthesis of stereo-defined α-trifluoromethyl arylenes is of great importance in medical chemistry, organic chemistry, and materials science. However, despite the recent advances, the Z-selective formation of α-trifluoromethyl arylenes has remained underdeveloped. Here, we describe a facile approach towards Z-α-trifluoromethyl arylenes through Pd-catalysed stereoselective fluoroarylation of 1,1-difluoroallenes in the presence of a bulky monophosphine ligand.

Ni-catalysed deamidative fluorination of amides with electrophilic fluorinating reagents.

We describe here a Ni-catalysed deamidative fluorination of diverse amides with electrophilic fluorinating reagents. Different types of amides including aromatic amides and olefinic amides were well compatible, affording the corresponding acyl fluorides in good to excellent yields.

Direct N-alkylation of sulfur-containing amines.

An efficient ruthenium-catalyzed method has been developed for the direct N-alkylation of sulfur-containing amines with alcohols, for the first time, by a step-economical and environmentally friendly hydrogen borrowing strategy. The present methodology features base-free conditions and broad substrate scope, with water being the only by-product. Moreover, this protocol has been applied to the synthesis of the pharmaceutical drug Quetiapine.

Regio- and Enantioselective Friedel-Crafts Benzhydrylation of Indoles in Carbocyclic Ring with ortho-Quinomethanes: Access to Chiral Diarylindolylmethanes.

The functionalization of indoles in the carbocyclic ring has been achieved via organocatalytic enantioselective Friedel-Crafts benzhydrylation of hydroxyindoles with in situ generated ortho-quinomethanes in oil-water biphases, allowing an efficient access to varied diarylindolylmethanes with a wide substrate scope. The high yields, excellent stereoselectivities, mild conditions, low catalyst loading, and easy scalability also demonstrated the interest of this novel methodology.

Nitrate promoted mild and versatile Pd-catalysed C(sp2)-H oxidation with carboxylic acids.

A nitrate-promoted Pd-catalysed mild cross-dehydrogenative C(sp2)-H bond oxidation of oximes or azobenzenes with diverse carboxylic acids has been developed. In contrast to the previous catalytic systems, this protocol features mild conditions (close to room temperature for most cases) and a broad substrate scope (up to 64 examples), thus constituting a versatile method to directly prepare diverse O-aryl esters. Moreover, the superiority of the nitrate additive in this mild transformation was further determined by experimental and computational evidence.

[Differential Reflectance Spectroscopy for In-Situ Monitoring of Organic Thin Films Growth in Vacuum Environment].

For realizing the real-time monitoring of organic thin film preparation process in vacuum environment, the present paper proposes a high precision measurement approach based on differential reflectance spectroscopy (DRS). An optical system was constructed with off the shelf optical components, such as off-axis parabolic mirror, optical flat and optical fiber. A differential algorithm was employed to analyze the spectral signals. Based on the homebuilt setup, instability induced by variation of temperature was investigated. It was concluded that with the good control of temperature and air flow, the measurement repeatability of this system is better than 2 per thousand for a long-term period. Furthermore, an initial stage of organic thin film growth of pentacene molecules on the surface of Au was studied. As compared with the data of film thickness gauge and atomic force microscope, DR spectra accurately recorded the fine optical evolution with sub-monolayer resolution, which is related to the growth of the thin film. As a result, the DR optical system exhibits characteristics of broad spectrum (range from 300 to 820 nm), high stability (repeatability better than 2X 10(-3)), and high precision (sub-monolayer resolution) after efforts were done to decrease the influences on the spectral quality produced by misalignments of the optical components, the defects of the optics, and the disturbances of the environmental conditions. It is indicated that the proposed DR method is suitable for real-time online monitoring of thin film growth with high precision.

Mild and versatile nitrate-promoted C-H bond fluorination.

A novel and facile C-H bond fluorination proceeds under remarkably mild conditions (close to room temperature in most cases). Both aromatic and olefinic C(sp(2))-H bonds with a wide range of electronic properties are selectively fluorinated in the presence of a catalytic amount of simple, cheap, and nontoxic nitrate as the promoter. A Pd(II)/Pd(IV) catalytic cycle that is initiated by an in situ generated cationic [Pd(NO3)](+) species was proposed based on preliminary mechanistic studies.

Prolinethiol ether catalysis in an asymmetric Michael reaction: solvent-free synthesis of functionalized monohaloalkenes.

The organocatalytic Michael reaction of ketones with γ-monohalonitrodienes catalyzed by chiral prolinethiol ether under solvent-free conditions was developed. The described method represents a novel approach for accessing highly functionalized monohaloalkenes with α, ß-stereocenters of up to >99% ee.

Non-directed Pd-catalysed C-H arylation of [2.2]paracyclophane.

We report herein the palladium-catalysed mono-selective C-H arylation of [2.2]paracyclophane (PCP) with diverse aryl iodides in the absence of any pendant directing groups, providing straightforward and modular access to C4-arylated [2.2]paracyclophanes. Moreover, a new PCP-containing biaryl monophosphine complex could be readily obtained through further derivation of the arylated product.

Single-Center Preliminary Experience with Gutter-Plugging Chimney Stent-Graft for Aortic Dissection.

PURPOSE: To report the early 2-year results and experience of a novel gutter-plugging chimney stent-graft in a single center that participated in the clinical trial of Prospective Study for Aortic Arch Therapy with stENt-graft for Chimney technology. MATERIALS AND METHODS: Patients diagnosed with aortic dissection were treated with the novel chimney stent-grafts named Longuette™ for the left subclavian artery revascularization. Primary study outcomes were the incidence of freedom from major adverse events within 30 days and success rate of the operation over 12 months. RESULTS: A total of 34 patients were enrolled between September 2019 and December 2020. The immediate technical success rate (stent-grafts successfully deployed without fast-flow type Ia or type III endoleak intraoperatively) was 100%, and there were no conversions to open repair. Type Ia and type II endoleaks were noted in three patients (8.8%) and one patient (2.9%) at discharge, respectively. One patient (2.9%) with type Ia endoleak underwent coil embolization at 12 months because of false lumen dilation, and one (2.9%) case of type Ia endoleak resolved spontaneously at 24 months. One chimney stent (2.9%) was revealed with stenosis at discharge and occluded with thrombosis at 6 months postoperatively. During the 2-year follow-up, there was no death, rupture, stroke, paraplegia, left arm ischemia, retrograde dissection, stent-graft induced new entry, or stent migration. CONCLUSION: The initial results of the Longuette™ stent-graft for revascularization of the left subclavian artery are encouraging with a high technical success rate. Further multicenter follow-up outcomes are required to assess the long-term durability. LEVEL OF EVIDENCE: Level 4, Case Series.

Rapid access to 9-arylfluorene and spirobifluorene through Pd-catalysed C-H arylation/deaminative annulation.

We describe here a facile synthesis of 9-arylfluorenes and spirobifluorenes from readily available 1,1-diarylmethylamines and iodoarenes through Pd-cataylsed C(sp2)-H arylation and a sequential deaminative annulation. The reaction features high efficiency and simplicity of operation, constituting an interesting shortcut to access fluorene compounds.

Pd-Catalysed direct C(sp2)-H fluorination of aromatic ketones: concise access to anacetrapib.

The Pd-cataylsed direct ortho-C(sp2)-H fluorination of aromatic ketones has been developed for the first time. The reaction features good regioselectivity and simple operations, constituting an alternative shortcut to access fluorinated ketones. A concise synthesis of anacetrapib has also been achieved by using late-stage C-H fluorination as a key step.

Pd-catalysed ß-selective C(sp3)-H arylation of simple amides.

An efficient Pd-catalysed ß-C(sp3)-H arylation of diverse native amides with aryl iodides was developed. This protocol overcomes the necessity of the Thorpe-Ingold effect and features broad substrate scope and good functional group tolerance. The potential application of this protocol is collectively demonstrated by gram-scale synthesis and the synthesis of several bioactive molecules.

In situ generation of highly reactive allenes from nitrocyclopropanes: controllable synthesis of enynes and enesters.

A new and efficient strategy for ring-opening reactions of nitrocyclopropanes is developed for the first time for the divergent synthesis of enynes and enesters via in situ generated highly reactive electron-deficient intermediate allenes. Controllable approaches resulted in enynes and enesters with up to 89% and 90% yields, respectively. The reaction features easy operation, involves green solvents and simple inorganic bases, and is transition-metal free.

Regioselective C(sp3)-H fluorination of ketones: from methyl to the monofluoromethyl group.

Herein, we report a novel strategy to access CH2F-containing ketones through Pd-catalysed ß-selective methyl C(sp3)-H fluorination. The reaction features high regioselectivity and a broad substrate scope, constituting a modular method for the late-stage transformation of the native methyl (CH3) into the monofluoromethyl (CH2F) group.

Cu-Catalyzed Regioselective C-H Alkylation of Benzimidazoles with Aromatic Alkenes.

Herein we report a novel Cu-catalyzed regioselective C2-H alkylation of benzimidazoles with aromatic alkenes. The reaction features exclusive regioselectivity and broad substrate scope in the intermolecular alkylation of benzimidazoles with terminal and internal aromatic alkenes, constituting a modular access toward benzimidazole-containing 1,1-di(hetero)aryl alkanes. The intramolecular C2-H alkylation of benzimidazoles with aromatic alkenes has been achieved in an endo-selective manner. The enantioselective C2 alkylation of benzimidazoles has also been realized with moderate to good stereocontrol.

Selective Cross-Dehydrogenative C(sp3)-H Arylation with Arenes.

Selective C(sp3)-C(sp2) bond construction is of central interest in chemical synthesis. Despite the success of classic cross-coupling reactions, the cross-dehydrogenative coupling between inert C(sp3)-H and C(sp2)-H bonds represents an attractive alternative toward new C(sp3)-C(sp2) bonds. Herein, we establish a selective inter- and intramolecular C(sp3)-H arylation of alcohols with nondirected arenes that thereby provides a general pathway to access a wide range of ß-arylated alcohols, including tetrahydronaphthalen-2-ols and benzopyran-3-ols, with high to excellent chemo- and regioselectivity.

Bacterial association and comparison between lung and intestine in rats.

The association between lung and intestine has already been reported, but the differences in community structures or functions between lung and intestine bacteria yet need to explore. To explore the differences in community structures or functions, the lung tissues and fecal contents in rats were collected and analyzed through 16S rRNA sequencing. It was found that intestine bacteria was more abundant and diverse than lung bacteria. In intestine bacteria, Firmicutes and Bacteroides were identified as major phyla while Lactobacillus was among the most abundant genus. However, in lung the major identified phylum was Proteobacteria and genus Pseudomonas was most prominent genus. On the other hand, in contrast the lung bacteria was more concentrated in cytoskeleton and function in energy production and conversion. While, intestine bacteria were enriched in RNA processing, modification chromatin structure, dynamics and amino acid metabolism. The study provides the basis for understanding the relationships between lung and intestine bacteria.

In situ enamine activation in aqueous salt solutions: highly efficient asymmetric organocatalytic Diels-Alder reaction of cyclohexenones with nitroolefins.

Deep-sea Diels-Alder: The asymmetric organocatalytic Diels-Alder reaction of cyclohexenones with aromatic nitroolefins can be carried out in seawater and brine. The reaction proceeds by an in situ enamine activation involving a one-step concerted addition pathway (see scheme).