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Selective functionaliz0ation of C(sp3)–H bonds is a straightforward and practical method to construct complex molecule skeletons. In this field, direct transformation of unactivated C(sp3)–H bonds into C(sp3)–SCF3 architectures is still a great challenge. We report a highly selective trifluoromethylthiolation of unactivated aliphatic C(sp3)–H bonds by combination of proton-coupled electron transfer (PCET) and hydrogen atom transfer (HAT) strategy. A wide range of structurally diverse alkyl trifluoromethyl sulfides are obtained. Furthermore, the use of two different photocatalysts can realize an unprecedented trifluoromethylthiolation and amidation cascade of different C(sp3)–H bonds. It can afford a good access to bifunctionalized molecules in synthetically useful yields. [ABSTRACT FROM AUTHOR]

In view of the problems such as large works of manual preparation of LKJ basic source data and excessive dependence on personal ability of data compilers, this paper proposes a LKJ data preparation technology based on technical data of train diagram, and a set of LKJ data preparation system is developed based on this technology. The system realizes intelligent identification of technical data of train diagram adopting Excel, and realizes transformation of technical data of train diagram into standard engineering data, then converts the engineering data into LKJ basic source data. It builds engineering database and realizes LKJ basic data management and preparation. Based on the engineering data of main line annunciator and station annunciator, it realizes automatic preparation of line frame data such as station, track and annunciator zoning, and realizes automatic preparation of display data such as slope, bend, bridge and tunnel according to the starting and ending mileage and line information of zoning. In order to facilitate the upgrading of LKJ basic source data, the system realizes the comparison and automatic update between LKJ basic source data and engineering data. The field test shows that it can realize automatic production of nearly 90% LKJ basic source data by this technology, which can effectively improve the production efficiency of data and reduce the intensity of data preparation.

Controlling the cross‐coupling reaction between two different radicals is a long‐standing challenge due to the process occurring statistically, which would lead to three products, including two homocoupling products and one cross‐coupling product. Generally, the cross‐coupling selectivity is achieved by the persistent radical effect (PRE) that requires the presence of a persistent radical and a transient radical, thus resulting in limited radical precursors. In this paper, a highly selective cross‐coupling of alkyl radicals with acyl radicals to construct C(sp2)−C(sp3) bonds, or with alkyl radicals to construct C(sp3)−C(sp3) bonds have been achieved with the readily available carboxylic acids and their derivatives (NHPI ester) as coupling partners. The success originates from the use of tridentate ligand (2,2′ : 6′,2′′‐terpyridine) to enable radical cross‐coupling process to Ni‐mediated organometallic mechanism. This protocol offers a facile and flexible access to structurally diverse ketones (up to 90 % yield), and also a new solution for the challenging double decarboxylative C(sp3)−C(sp3) coupling. The broad utility and functional group tolerance are further illustrated by the late‐stage functionalization of natural‐occurring carboxylic acids and drugs. [ABSTRACT FROM AUTHOR]

α‐Trifluoromethyl alkenes are versatile CF3‐containing feedstocks. They have been widely used to construct gem‐difluoroalkene scaffolds through β−F elimination. The application of α−CF3 alkenes as trifluoromethylating reagents has been less explored. Herein, we report an efficient route for the synthesis of β‐trifluoromethylated ketones from readily accessed α−CF3 styrenes and aromatic carboxylic acids under photoredox catalysis. The reactions proceed by phosphoranyl radical promoted deoxygenation of aromatic acids, generating acyl radicals for subsequent hydroacylation of α−CF3 styrenes. The valuable trifluoromethyl‐containing compounds could be produced in good yields under mild conditions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: In this paper, we have developed a decarboxylative amination of carboxylic acids with nitroarenes for the synthesis of secondary amines. The protocol is performed at mild conditions without the use of noble metals as catalysts. A wide range of structurally diverse secondary amines could be obtained in good yields (up to 94%) with good functional group tolerance. This transformation shows good to excellent selectivity, avoiding the generation of over alkylated byproducts. [ABSTRACT FROM AUTHOR]

In recent years, the activation of unactivated alkyl chlorides through light-induced processes has emerged as a promising field in radical chemistry, and has led to new transformations in organic synthesis. Direct utilization of alkyl chlorides as C(sp3)-hybridized electrophiles enables the facile construction of carbon–carbon and carbon–heteroatom bonds. Furthermore, recent studies in medicinal chemistry indicate that their presence is associated with high levels of success in clinical trials. This review summarizes the recent advances in the photoinduced activation of unactivated alkyl chlorides and discusses the mechanistic aspects underlying these reactions. We anticipate that this review will serve as a valuable resource for researchers in the field of unactivated chemical bond functionalization, and inspire considerable developments in organic chemistry, drug synthesis, materials science and other related disciplines. [ABSTRACT FROM AUTHOR]

The alkyne unit is a versatile building block in organic synthesis and the development of selective multifunctionalization of alkynes is an important object of research in this field. Herein, we report an interesting gold-catalyzed, four-component reaction that achieves the oxo-arylfluorination or oxo-arylalkenylation of internal aromatic or aliphatic alkynes, efficiently breaking a carbon-carbon triple bond and forming four new chemical bonds. The reaction divergence can be controlled by site-directing functional groups in the alkynes; the presence of a phosphonate unit favors the oxo-arylfluorination, while the carboxylate motif benefits oxo-arylalkenylation. This reaction is enabled by an Au(I)/Au(III) redox coupling process using Selectfluor as both an oxidant and a fluorinating reagent. A wide range of structurally diverse α,α-disubstituted ketones, and tri- or tetra-substituted unsaturated ketones have been prepared in synthetically valuable yields and with excellent chemo-, regio- and stereoselectivity. The gram-scale preparation and late-stage application of complex alkynes have further enhanced their synthetic value. The development of selective multifunctionalization of alkynes is essential for organic synthesis with alkyne units as building blocks. Here the authors report a gold-catalyzed, four-component reaction that achieves the oxo-arylfluorination or oxo-arylalkenylation of internal aromatic or aliphatic alkynes [ABSTRACT FROM AUTHOR]

The paper introduced magnetic flux leakage testing principle of wire rope flaw detector, and used finite element analysis method to analyze impact factors of detection results of wire rope flaw detector based on flux leakage testing principle, the impact factors include material of sensor parts, rope lift-off distance and number of broken wires. The analysis results show that the factors of lift-off distance and the number of broken wires have large impact on detection results of wire rope flaw detector, and the factors of angle and depth of broken wires has little impact on detection results of wire rope flaw detector.

For problems of exiting flame sensors based on infrared detection principle such as short detection distance, long response time and so on, a mine-used flame sensor was developed based on ultraviolet light detection principle. Mathematical model of signal modulation circuit of ultraviolet phototube was established through experiments for calculating circuit parameters to improve response speed of the ultraviolet phototube. Power source and signal transmission circuit were designed with electro magnetic compatibility, so as to improve anti-interference ability of the sensor. The test result shows that the sensor has fast response speed, strong anti-interference ability and good stability and reliability.