Gold-Catalyzed Cascade Reaction of Diynamides with Allylic Alcohols: A Versatile Platform to Allenamide, 2-Aminofuran and Bridged [2.2.2]Octadiene Derivatives.

Transition metal-catalyzed divergent synthesis through alternation of the catalyst is appealing, as it provides an operationally simple way to access different valuable products, while using the same reactants as starting materials. Herein, a gold-catalyzed cascade reaction of conjugated diynamides with allylic alcohols is described. By variation of the catalysts, substituted allenes and furans could be obtained selectively. Mechanistic studies indicate that, after the addition of allylic alcohol to gold-activated diynamide, a [3,3]-sigmatropic rearrangement would take place and lead to the formation of a common reactive intermediate, which would further convert to the final products selectively. Further variation of the structure of diynamides has unveiled an additional reaction sequence involving intramolecular Himbert arene/allene Diels-Alder cycloaddition to afford a series of dearomatized products bearing bicyclo[2,2,2]octadiene core.

Alkyne Insertion Enabled Vinyl to Acyl 1,5-Palladium Migration: Rapid Access to Substituted 5-Membered-Dihydrobenzofurans and Indolines.

"Through space" palladium/hydrogen shift is an efficient strategy to achieve selective functionalization of a specific remote C-H bond. Compared with relatively extensive exploited 1,4-palladium migration process, the relevant 1,5-Pd/H shift was far less investigated. We herein report a novel 1,5-Pd/H shift pattern between a vinyl and an acyl group. Through the pattern, rapid access to 5-membered-dihydrobenzofuran and indoline derivatives has been achieved. Further studies have unveiled an unprecedented trifunctionalization (vinylation, alkynylation and amination) of a phenyl ring through 1,5-palladium migration relayed decarbonylative Catellani type reaction. A series of mechanistic investigations and DFT calculations have provided insights into the reaction pathway. Notably, it was unveiled that the 1,5-palladium migration in our case prefers a stepwise mechanism involving a PdIV intermediate.

Efficient access to 1,3,4-trisubstituted pyrroles via gold-catalysed cycloisomerization of 1,5-diynes.

A gold-catalysed cycloisomerization of 1,5-diynes is described, which offers a selective approach to access 1,3,4-trisubstituted pyrroles. In this reaction, the cationic gold catalyst activates the ynamide moiety, initiating the cycloisomerization to produce the pyrrole core, and H2O acts as an external nucleophile to trap the vinyl cationic species, thus leading to the formation of 1,3,4-trisubstituted pyrroles with high selectivity.

Toward Robust Non-Intrusive Load Monitoring via Probability Model Framed Ensemble Method.

As a pivotal technological foundation for smart home implementation, non-intrusive load monitoring is emerging as a widely recognized and popular technology to replace the sensors or sockets networks for the detailed household appliance monitoring. In this paper, a probability model framed ensemble method is proposed for the target of robust appliance monitoring. Firstly, the non-intrusive load disaggregation-oriented ensemble architecture is presented. Then, dictionary learning model is utilized to formulate the individual classifier, while the sparse coding-based approach is capable of providing multiple solutions under greedy mechanism. Furthermore, a fully probabilistic model is established for combined classifier, where the candidate solutions are all labelled with probability scores and evaluated via two-stage decision-making. The proposed method is tested on both low-voltage network simulator platform and field measurement datasets, and the results show that the proposed ensemble method always guarantees an enhancement on the performance of non-intrusive load disaggregation. Besides, the proposed approach shows high flexibility and scalability in classification model selection. Therefore, by initializing the architecture and approach of ensemble method-based NILM, this work plays a pioneer role in using ensemble method to improve the robustness and reliability of non-intrusive appliance monitoring.

An Enhanced Ensemble Approach for Non-Intrusive Energy Use Monitoring Based on Multidimensional Heterogeneity.

Acting as a virtual sensor network for household appliance energy use monitoring, non-intrusive load monitoring is emerging as the technical basis for refined electricity analysis as well as home energy management. Aiming for robust and reliable monitoring, the ensemble approach has been expected in load disaggregation, but the obstacles of design difficulty and computational inefficiency still exist. To address this, an ensemble design integrated with multi-heterogeneity is proposed for non-intrusive energy use disaggregation in this paper. Firstly, the idea of utilizing a heterogeneous design is presented, and the corresponding ensemble framework for load disaggregation is established. Then, a sparse coding model is allocated for individual classifiers, and the combined classifier is diversified by introducing different distance and similarity measures without consideration of sparsity, forming mutually heterogeneous classifiers. Lastly, a multiple-evaluations-based decision process is fine-tuned following the interactions of multi-heterogeneous committees, and finally deployed as the decision maker. Through verifications on both a low-voltage network simulator and a field measurement dataset, the proposed approach is demonstrated to be effective in enhancing load disaggregation performance robustly. By appropriately introducing the heterogeneous design into the ensemble approach, load monitoring improvements are observed with reduced computational burden, which stimulates research enthusiasm in investigating valid ensemble strategies for practical non-intrusive load monitoring implementations.

Divergent synthesis of 1,3,5-tri and 1,3-disubstituted pyrazoles under transition metal-free conditions.

Pyrazole cores are common structural motifs existing in various agrochemicals and pharmaceuticals. Herein, a transition metal-free, three-component reaction of arylaldehydes, ethyl acrylate and N-tosylhydrazones is described, which leads to the formation of 1,3,5-trisubstituted and 1,3-disubstituted pyrazoles divergently under slightly different conditions.

Facile access to 2,2-diaryl 2H-chromenes through a palladium-catalyzed cascade reaction of ortho-vinyl bromobenzenes with N-tosylhydrazones.

A palladium-catalyzed cascade reaction of ortho-vinyl bromobenzenes with N-tosylhydrazones has been developed, which provides a facile approach to 2,2-disubstituted 2H-chromenes. The migration of palladium from the aryl to vinyl position is crucial, as the in situ produced vinyl palladium intermediate could further react with diazo compounds to generate the reactive species for the sequential annulation.

A Modular Approach to Dibenzo-fused ϵ-Lactams: Palladium-Catalyzed Bridging-C-H Activation.

Tricyclic ring systems possessing a dibenzo structure joined to a seven-membered heterocyclic ring frequently show important biological activities. However, a modular approach to these molecules based on efficient intermolecular reaction of readily available chemicals is lacking. Herein, an unprecedented palladium-catalyzed formal [4+3] annulation for modular construction of these tricyclic systems is described. This reaction features easily accessible reactants (o-haloarylaldehydes and N-tosylhydrazones), broad substrate scope, and excellent functional group compatibility. The synthetic potential is demonstrated by the easy scale-up reactions, late-stage modification of complex molecules, and collective synthesis of bioactive molecules and approved drugs.

Palladium-Catalyzed Intermolecular Acylation of Aryl Diazoesters with ortho-Bromobenzaldehydes.

In this work, we describe a palladium-catalyzed intermolecular O acylation of α-diazoesters with ortho-bromobenzaldehydes. The C(sp2 )-H bond activation of the aldehyde is enabled by migratory insertion of a palladium carbene intermediate. The diazoesters act as modular three-atom units to build up key seven-membered palladacycles, which are transformed into a variety of isocoumarin derivatives upon reductive elimination. Mechanistic experiments and DFT calculations provide insight into the reaction pathway.

Amination of Diazocarbonyl Compounds: N-H Insertion under Metal-Free Conditions.

Transition-metal-free intermolecular N-H insertion of α-diazocarbonyl compounds is reported. Among the series of nitrogen sources examined, dibenzenesulfonimide was found to be the choice in terms of the yields and the reaction time. Primary mechanistic experiments suggest that a pathway involving a sequence of protonation and nucleophilic substitution was preferred.

Gold-Catalyzed ß-Regioselective Formal [3 + 2] Cycloaddition of Ynamides with Pyrido[1,2-b]indazoles: Reaction Development and Mechanistic Insights.

Here, we report an unprecedented gold(I)-induced ß-site regioselective formal [3 + 2] cycloaddition of ynamides with pyrido[1,2-b]indazoles, giving 3-amido-7-(pyrid-2'-yl)indoles in good to excellent yields. A complex of gold(I) catalyst with ynamide was isolated and characterized by X-ray diffraction analysis for the first time. Mechanistic investigations suggest the reaction pathway involves a gold-stabilized carbocation intermediate, which in turn participated in sequential C-H bond functionalization of the ortho-position of the phenyl ring.

Facile synthesis of substituted 3-aminofurans through a tandem reaction of N-sulfonyl-1,2,3-triazoles with propargyl alcohols.

A relay catalysis strategy for substituted 3-aminofurans synthesis has been developed. This transformation involves a tandem reaction sequence through aza-vinyl-rhodium(ii) carbene O-H bond insertion, thermal propargyl-Claisen rearrangement and gold(i)-catalyzed intramolecular cyclization. More importantly, the current strategy employs simple feedstocks as starting materials, providing substituted 3-aminofurans in a highly efficient manner.

Polysubstituted 2-Aminopyrrole Synthesis via Gold-Catalyzed Intermolecular Nitrene Transfer from Vinyl Azide to Ynamide: Reaction Scope and Mechanistic Insights.

A gold-catalyzed intermolecular reaction of vinyl azides and ynamides is described. This process presents an efficient and mild approach to multisubstituted 2-aminopyrroles in good-to-excellent yields. Control experiments were carried out to distinguish the reactivity between vinyl azides and the corresponding 2H-azirines. A plausible reaction mechanism was also proposed according to previous reports and our preliminary mechanistic studies.

Stereoselective gold(I) domino catalysis of allylic isomerization and olefin cyclopropanation: mechanistic studies.

Gold(I) catalysis of olefin activation is still a rare feature in the repertoire of that metal. Mechanistic studies on the gold(I)-catalyzed cyclopropanation of allyl-substituted sulfonium ylides, including kinetic analysis as well as detailed computational studies, reveal that the reaction proceeds through activation of the alkene moiety. Furthermore, a novel competitive allylic isomerization pathway that interconverts "linear" and "branched" allylic isomers is uncovered. The subtle interplay of cyclopropanation and olefin isomerization results in an intriguing domino process where two independent catalytic transformations combine with near-perfect regio- and stereoselectivities.

Dimeric TADDOL Phosphoramidites in Asymmetric Catalysis: Domino Deracemization and Cyclopropanation of Sulfonium Ylides.

A gold-catalyzed asymmetric cyclopropanation of unactivated olefins with sulfonium ylides in the presence of a bimetallic catalyst with a novel dimeric TADDOL-phosphoramidite ligand is reported. This transformation allows a rare gold-catalyzed dynamic deracemization of chiral racemic substrates, where the same catalyst is responsible for several synergistic tasks in solution. The products are useful building blocks in synthesis and enable expeditious access to natural products.

Gold-catalyzed intermolecular synthesis of alkylidenecyclopropanes through catalytic allene activation.

A stereoselective gold(I)-catalyzed intermolecular cyclopropanation of allenamides with stabilized sulfonium ylides is reported. This transformation enables the direct synthesis of diacceptor alkylidenecyclopropanes and proceeds under very mild conditions through allene activation.

A Brønsted acid catalyzed redox arylation.

A Brønsted acid catalyzed redox arylation of ynamides that employs aryl sulfoxides as the arylating agents is reported. This metal-free transformation proceeds at room temperature and efficiently affords α-arylated oxazolidinones in a redox-neutral, atom-economic fashion.

Sulfur(IV)-mediated transformations: from ylide transfer to metal-free arylation of carbonyl compounds.

The development of a direct ylide transfer to carbonyl derivatives and of a sulfoxide-mediated arylation is presented from a unified perspective. Mechanistic studies (including density functional calculations) support a common reaction pathway and showcase how subtle changes in reactant properties can lead to disparate and seemingly unrelated reaction outcomes.

Resistance optimization of a coil with substrate and design of a high-power-density coupler for wireless power transfer.

Wireless power transfer (WPT) technology has been popularized due to its convenience, safety, and unmanned nature. To improve the transmission performance of couplers and reduce the magnetic field, the designers of such couplers often adopt a combination of coils and substrates: however, the non-ferromagnetic substrate often leads to the enhancement of coil equivalent resistance and the decrease of the efficiency of a WPT system. In the present work, the effect of a substrate on coil equivalent resistance is evaluated by finite element simulation. The effects of the distance between a substrate and a coil and the number of turns of coil on the equivalent resistance of coils are studied. Based on the calculation method of alternating current resistance for Litz-wire, the equivalent resistance reduction method involving use of a coil with substrates is proposed to significantly reduce equivalent resistance of the coil with its substrate. A high-power-density coupler is designed based on the above method. The power densities of a transmitting coil and a receiving coil are only 0.542 W/cm 3 and 0.81 W/cm 3 respectively. When the transmission distance is 200 mm, a power transmission of 3.61 kW is realized, and the efficiency of the coupler and system reaches 94.61% and 92.56%, respectively.

Sex-specific non-linear associations between body mass index and impaired pulmonary ventilation function in a community-based population: Longgang COPD study.

Aim: To investigate the prevalence of pulmonary airflow limitation and its association with body mass index (BMI) in a community-based population in Shenzhen, China. Methods: Study participants were recruited from Nanlian Community in Shenzhen, China, and spirometry was performed to assess lung function including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, and FEV1 divided by predicted value. Pulmonary airflow limitation was determined by the Chinese Guideline of Pulmonary Function Examination. Multivariable logistic regression models were used to examine the association between BMI and pulmonary airflow limitation. Age, sex, educational attainment, occupation, and current cigarette smoking were used as potential confounders. Results: Of the 1206 participants, 612 (50.7%) were men and 594 (49.3%) were women with the average age being 53.7 years old. After adjusting for age, sex, educational attainment, occupation, and current cigarette smoking, higher BMI was associated with lower odds (odds ratio: 0.98, 95% confidence interval: 0.97, 0.99) of pulmonary airflow limitation by assuming a linear relationship. Further investigation of the interaction terms, we found that the magnitudes of the associations differed in men and women. A U-shaped relationship was observed in women, while the association was almost linear in men. Conclusion: The relationship between BMI and pulmonary airflow limitation was U-shaped in women and linear in men.